One path walk under checkPath, descend, readField, pathLeaves and coverPath; split the hold and the render graph into their own files
Tests / vet + fmt + tests (pull_request) Successful in 53s
Tests / vet + fmt + tests (pull_request) Successful in 53s
This commit is contained in:
@@ -402,16 +402,19 @@ GO_VERSION=1.22.12 docker compose run --rm test # the same tests, without the im
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## Layout
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```
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fejkdata.go Generator, New, options, the embedded data set, List
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node.go the node model and JSON -> node compilation
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render.go Fake and the recursive renderer (choices, format strings, paths, held draws)
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template.go the {token} grammar: scanning, arms, operands, validation
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reference.go {/path} binding across the tree, the render graph, and the walks over it
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builtins.go the {name()} function registry and its implementations
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calc.go the {calc()} arithmetic evaluator: parser, eval, validation
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data.go data loading: fs.FS folders/files -> namespace tree, multi-source merge
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cmd/fejkdata/ the fejkdata CLI
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data/ shipped data (JSON), embedded at build: locale folders + a misc folder
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fejkdata.go Generator, New, options, the embedded data set, List
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node.go the node model and JSON -> node compilation
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path.go the dotted-path walk, and proving a path resolves
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render.go Fake and the recursive renderer (choices, format strings, expansions)
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template.go the {token} grammar: scanning, tokens, operands, validation, compiling a format
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hold.go the hold: one draw per expansion for paths and operands, and its fences
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reference.go reference sigils, and binding references across the tree
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graph.go the render graph: edges, cycles, the repeat bound, tree walks
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builtins.go the {name()} function registry and its implementations
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calc.go the {calc()} arithmetic evaluator: parser, eval, validation
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data.go data loading: fs.FS folders/files -> namespace tree, multi-source merge
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cmd/fejkdata/ the fejkdata CLI
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data/ shipped data (JSON), embedded at build: locale folders + a misc folder
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```
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## License
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@@ -0,0 +1,222 @@
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package fejkdata
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import (
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"fmt"
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"sort"
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"strings"
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)
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// walkNodes calls fn once per contained node, passing the dot path that reaches it,
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// visiting keys in sorted order so which of several broken nodes gets reported does
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// not depend on map iteration.
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func walkNodes(root map[string]node, fn func(path string, n node) error) error {
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seen := map[node]bool{}
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var visit func(string, node) error
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visit = func(path string, n node) error {
|
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if n == nil || seen[n] {
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return nil
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}
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seen[n] = true
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if err := fn(path, n); err != nil {
|
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return err
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}
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for _, c := range contained(n) {
|
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if err := visit(join(path, c.name), c.node); err != nil {
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return err
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}
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}
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return nil
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}
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for _, name := range sortedNames(root) {
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if err := visit(name, root[name]); err != nil {
|
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return err
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}
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}
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return nil
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}
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// namedNode is a contained child and the segment reaching it; a choice's items carry
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// no segment, matching how a dot path steps over a choice.
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type namedNode struct {
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name string
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node node
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}
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|
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func contained(n node) []namedNode {
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switch n := n.(type) {
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case *group:
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return named(n.children)
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case *choice:
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out := make([]namedNode, len(n.items))
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for i, it := range n.items {
|
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out[i] = namedNode{node: it}
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}
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return out
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case *template:
|
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return named(n.fields)
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default:
|
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return nil
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}
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}
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// named skips a bound {/path} key: it is a render edge, not containment, so using
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// it as a path segment would report a node under a path that does not reach it. Only
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// a template's fields hold bindings — loadDir skips a dot-prefixed entry, so a
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// group's children never carry the prefix — so this one skip serves both.
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func named(m map[string]node) []namedNode {
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out := make([]namedNode, 0, len(m))
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for _, name := range sortedNames(m) {
|
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if isRef(name) {
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continue
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}
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out = append(out, namedNode{name: name, node: m[name]})
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}
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return out
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}
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func sortedNames(m map[string]node) []string {
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names := make([]string, 0, len(m))
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for name := range m {
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names = append(names, name)
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}
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sort.Strings(names)
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return names
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}
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// renderEdge is a child a node renders into, labelled by what reaches it (a field
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// name, reference, or choice index) for a readable cycle report. operand names
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// the builtin when the label is its operand rather than a token, so an error can
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// name it the way the author wrote it.
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type renderEdge struct {
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to node
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label string
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operand string
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}
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// reached names an edge as the author spelled it, the vocabulary boundReaders uses
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// for the sibling fence.
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func (e renderEdge) reached() string {
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if e.operand != "" {
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return fmt.Sprintf("%s operand %q", e.operand, e.label)
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}
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return "{" + e.label + "}"
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}
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// renderEdges lists the children rendering n recurses into, mirroring expand: a
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// choice's items, and a template's field/reference tokens plus its operands. A
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// group renders nothing, so it has no edges.
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func renderEdges(n node) []renderEdge {
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switch n := n.(type) {
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case *choice:
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es := make([]renderEdge, len(n.items))
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for i, it := range n.items {
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es[i] = renderEdge{to: it, label: fmt.Sprintf("[%d]", i)}
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}
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return es
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case *template:
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var es []renderEdge
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add := func(name, operand string) {
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a := splitArm(name, n.refs)
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c, ok := n.fields[a.key]
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if !ok {
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return
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}
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for _, leaf := range pathLeaves(c, a.tail) {
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es = append(es, renderEdge{leaf, name, operand})
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}
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}
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_ = eachToken(n.format, func(t ftoken) error {
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if t.kind != 'b' {
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return nil
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}
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if fn, _, isFunc := funcCall(t.body); isFunc {
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for _, operand := range tokenOperands(t.body) {
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add(operand, fn)
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}
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return nil
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}
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for _, name := range strings.Split(t.body, "|") {
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add(name, "")
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}
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return nil
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})
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return es
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default:
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return nil
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}
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}
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// pathLeaves lists what a token's dotted tail renders: a choice on the way
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// contributes every variant, since any of them may be the one drawn. checkPath has
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// already proved the tail resolves in every variant.
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func pathLeaves(n node, tail []string) []node {
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var out []node
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_ = walkPath(n, tail, pathWalk{
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choice: func(c *choice, _ []string) ([]node, error) { return c.items, nil },
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leaf: func(n node) error { out = append(out, n); return nil },
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})
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return out
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}
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// checkRepeatReach bounds the renders a repeat multiplies to along any root-to-leaf
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// path, so nested repeats cannot build what one repeat may not. It runs after
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// checkNoCycles, whose guarantee is what lets the walk terminate.
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func checkRepeatReach(root map[string]node) error {
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reach := map[node]int{}
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var of func(n node) int
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of = func(n node) int {
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if r, done := reach[n]; done {
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return r
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}
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r := 1
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for _, e := range renderEdges(n) {
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if c := of(e.to); c > r {
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r = c
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}
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}
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if t, ok := n.(*template); ok {
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r *= t.repeat
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}
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reach[n] = r
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return r
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}
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return walkNodes(root, func(path string, n node) error {
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if t, ok := n.(*template); ok && t.repeat > 1 && of(n) > maxLen {
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return fmt.Errorf("%s: repeat %d multiplies to %d renders along one path, above the maximum %d", path, t.repeat, of(n), maxLen)
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}
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return nil
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})
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}
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// checkNoCycles rejects a reference cycle: a node whose rendering can reach itself
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// — directly, mutually, or through a chain — never terminates, so it must fail at
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// New rather than stack-overflow at render. It is a depth-first walk of the render
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// graph (renderEdges); grey marks nodes on the current path so a back-edge to one
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// is the cycle, while black lets a shared node (a DAG, not a cycle) be skipped.
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// Every node is a root: a field its parent's format never renders is still reachable
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// by dot path, so a cycle in one would otherwise reach render and be fatal there.
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func checkNoCycles(root map[string]node) error {
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const (
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grey = 1
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black = 2
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)
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color := map[node]int{}
|
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var visit func(n node, path string) error
|
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visit = func(n node, path string) error {
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switch color[n] {
|
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case grey:
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return fmt.Errorf("reference cycle: %s", path)
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case black:
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return nil
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}
|
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color[n] = grey
|
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for _, e := range renderEdges(n) {
|
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if err := visit(e.to, path+" -> "+e.label); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
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color[n] = black
|
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return nil
|
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}
|
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return walkNodes(root, func(path string, n node) error { return visit(n, path) })
|
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}
|
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@@ -0,0 +1,345 @@
|
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package fejkdata
|
||||
|
||||
import (
|
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"fmt"
|
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"sort"
|
||||
"strings"
|
||||
)
|
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|
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// checkBoundLevelsHeld rejects every route to a held name except the ones that read
|
||||
// its draw. An expansion holds one draw of that name; anything else that renders it
|
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// draws again, and the two disagree. checkNoOverlap settles the spellings within one
|
||||
// format (a token, an operand); this settles the rest — a reference, whether it
|
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// sits in that format or in anything the format renders, however deep.
|
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//
|
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// It runs after checkNoCycles, whose guarantee is what lets the walk terminate.
|
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func checkBoundLevelsHeld(root map[string]node) error {
|
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return walkNodes(root, func(path string, n node) error {
|
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t, ok := n.(*template)
|
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if !ok || len(t.held) == 0 {
|
||||
return nil
|
||||
}
|
||||
heads := make([]string, 0, len(t.held))
|
||||
for head := range t.held {
|
||||
heads = append(heads, head)
|
||||
}
|
||||
// Operand heads first, then paths, each in name order: a level read both
|
||||
// ways is reported by the operand's fence, and which overlap is reported
|
||||
// does not vary.
|
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sort.Slice(heads, func(i, j int) bool {
|
||||
_, pi := t.bound[heads[i]]
|
||||
_, pj := t.bound[heads[j]]
|
||||
if pi != pj {
|
||||
return !pi
|
||||
}
|
||||
return heads[i] < heads[j]
|
||||
})
|
||||
readers := boundReaders(t.format, t.bound, t.refs)
|
||||
for _, head := range heads {
|
||||
// What one draw answers for depends on how the draw is read: a path pins
|
||||
// the levels it passes through and the leaf it lands on, an operand
|
||||
// exactly the value its render produces.
|
||||
held := map[node]bool{}
|
||||
reader, isPath := t.bound[head]
|
||||
if isPath {
|
||||
for _, r := range readers {
|
||||
if a := splitArm(r.name, t.refs); a.key == head {
|
||||
coverPath(t.fields[head], a.tail, held)
|
||||
}
|
||||
}
|
||||
} else {
|
||||
operandDraw(t.fields[head], held)
|
||||
}
|
||||
if len(held) == 0 {
|
||||
continue // an early out: a fixed head holds nothing to reach
|
||||
}
|
||||
// One seen set across the edges: a node that cannot reach the level
|
||||
// cannot reach it by another route either, so it is walked once here.
|
||||
seen := map[node]bool{}
|
||||
for _, e := range renderEdges(t) {
|
||||
if splitArm(e.label, t.refs).key == head {
|
||||
continue // a token or operand reading this draw, the routes allowed
|
||||
}
|
||||
if renders(e.to, held, seen) {
|
||||
if isPath {
|
||||
return fmt.Errorf("%s: %s renders %q, which {%s} reads a path into; name the fields you want instead", path, e.reached(), head, reader)
|
||||
}
|
||||
return fmt.Errorf("%s: %s renders %q, which a {%s()} also reads; reach it one way so it is drawn once", path, e.reached(), head, operandReader(t, head))
|
||||
}
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
}
|
||||
|
||||
// operandReader names the builtin whose operand holds head.
|
||||
func operandReader(t *template, head string) string {
|
||||
fn := ""
|
||||
_ = eachToken(t.format, func(tok ftoken) error {
|
||||
if tok.kind != 'b' || fn != "" {
|
||||
return nil
|
||||
}
|
||||
if name, _, isFunc := funcCall(tok.body); isFunc {
|
||||
for _, operand := range tokenOperands(tok.body) {
|
||||
if splitArm(operand, t.refs).key == head {
|
||||
fn = name
|
||||
}
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
return fn
|
||||
}
|
||||
|
||||
// coverPath collects what holding one path pins: every choice level the path
|
||||
// passes through, whole, and the leaf it renders.
|
||||
func coverPath(n node, tail []string, into map[node]bool) {
|
||||
_ = walkPath(n, tail, pathWalk{
|
||||
choice: func(c *choice, _ []string) ([]node, error) { cover(c, into, false); return nil, nil },
|
||||
leaf: func(n node) error { cover(n, into, false); return nil },
|
||||
})
|
||||
}
|
||||
|
||||
// cover collects a level and everything contained in it. A fixed string outside a
|
||||
// choice is left out — it cannot disagree with itself — but inside one each
|
||||
// variant carries its own, so there it counts.
|
||||
func cover(n node, into map[node]bool, inChoice bool) {
|
||||
if isFixed(n) && !inChoice {
|
||||
return
|
||||
}
|
||||
into[n] = true
|
||||
_, isChoice := n.(*choice)
|
||||
for _, c := range contained(n) {
|
||||
cover(c.node, into, inChoice || isChoice)
|
||||
}
|
||||
}
|
||||
|
||||
// operandDraw collects what one held draw of an operand answers for: the operand
|
||||
// and what rendering it settles inside itself. The builtin renders its operand
|
||||
// whole, so that draw fixes every value the render produced, and a second route to
|
||||
// any of them disagrees with it.
|
||||
//
|
||||
// The walk stops at a reference edge, which is where the operand's own value ends
|
||||
// and a shared source begins: two names referencing one category are two draws, the
|
||||
// same rule {word} {word} follows.
|
||||
func operandDraw(n node, into map[node]bool) {
|
||||
if isFixed(n) {
|
||||
return
|
||||
}
|
||||
if into[n] {
|
||||
return
|
||||
}
|
||||
into[n] = true
|
||||
for _, e := range renderEdges(n) {
|
||||
if isRef(e.label) {
|
||||
continue
|
||||
}
|
||||
operandDraw(e.to, into)
|
||||
}
|
||||
}
|
||||
|
||||
// isFixed is a string that varies nothing: fixed text with no fields to read into.
|
||||
func isFixed(n node) bool {
|
||||
t, ok := n.(*template)
|
||||
return ok && t.fixed && len(t.fields) == 0
|
||||
}
|
||||
|
||||
// renders reports whether rendering n can reach anything in want, following the
|
||||
// same edges expand does. seen keeps a node shared by several routes from being
|
||||
// walked twice; checkNoCycles has already proved the graph is a DAG, so the walk
|
||||
// ends.
|
||||
func renders(n node, want, seen map[node]bool) bool {
|
||||
if want[n] {
|
||||
return true
|
||||
}
|
||||
if seen[n] {
|
||||
return false
|
||||
}
|
||||
seen[n] = true
|
||||
for _, e := range renderEdges(n) {
|
||||
if renders(e.to, want, seen) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// arm is one alternative of a {a|b} token or one operand, split into the key
|
||||
// naming the node in a template's fields (a sibling field, or the head a
|
||||
// reference is bound under) and the tail of a dotted path into it. A non-empty
|
||||
// tail is what makes the arm a bound draw: its head is drawn once per expansion
|
||||
// (see compileOps).
|
||||
type arm struct {
|
||||
name string // as written, and the key a bound draw's value is held under
|
||||
key string
|
||||
tail []string
|
||||
steps []string // key per level passed through; the head and leaf hold their own
|
||||
}
|
||||
|
||||
// splitArm splits one name into key and tail. refs maps a reference to what
|
||||
// linkRefs bound it to; before linking, a reference is whole.
|
||||
func splitArm(name string, refs map[string]refBinding) arm {
|
||||
if isRef(name) {
|
||||
b, bound := refs[name]
|
||||
if !bound || len(b.tail) == 0 {
|
||||
key := name
|
||||
if bound {
|
||||
key = b.key
|
||||
}
|
||||
return arm{name: name, key: key}
|
||||
}
|
||||
return pathArm(name, b.key, b.tail)
|
||||
}
|
||||
head, tail, dotted := strings.Cut(name, ".")
|
||||
if !dotted {
|
||||
return arm{name: name, key: name}
|
||||
}
|
||||
return pathArm(name, head, strings.Split(tail, "."))
|
||||
}
|
||||
|
||||
func pathArm(name, key string, segs []string) arm {
|
||||
var steps []string
|
||||
for i := 0; i < len(segs)-1; i++ { // every level except the leaf's own
|
||||
steps = append(steps, key+"."+strings.Join(segs[:i+1], "."))
|
||||
}
|
||||
return arm{name: name, key: key, tail: segs, steps: steps}
|
||||
}
|
||||
|
||||
// checkNoOverlap rejects a format that both renders a level and reads a path into
|
||||
// it — {p} beside {p.first}, or {p.addr} beside {p.addr.city}. The path reads the
|
||||
// level's held draw while rendering the level expands it afresh, so their values
|
||||
// would disagree. Names are compared in sorted order, so which pair is reported
|
||||
// does not depend on where the tokens sit.
|
||||
func checkNoOverlap(format string, bound map[string]string, refs map[string]refBinding) error {
|
||||
names := boundReaders(format, bound, refs)
|
||||
// Stable over one format-order scan, so two readers of one name (a token and a
|
||||
// calc operand both naming "p") are reported as the format writes them.
|
||||
sort.SliceStable(names, func(i, j int) bool { return names[i].name < names[j].name })
|
||||
for i, level := range names {
|
||||
for _, path := range names[i+1:] {
|
||||
if strings.HasPrefix(path.name, level.name+".") {
|
||||
return fmt.Errorf("%s renders a level that {%s} reads a path into; name the fields you want instead", level.label, path.name)
|
||||
}
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// reader is one way a format reaches a bound field, and how to name that spelling.
|
||||
type reader struct{ name, label string }
|
||||
|
||||
// boundReaders lists every way a format reaches a bound field, in the order the
|
||||
// format writes them. An operand renders its field, so it names a level exactly
|
||||
// as a token does; one scan finds both, which is what puts them in one order.
|
||||
func boundReaders(format string, bound map[string]string, refs map[string]refBinding) []reader {
|
||||
var names []reader
|
||||
_ = eachToken(format, func(t ftoken) error {
|
||||
if t.kind != 'b' {
|
||||
return nil
|
||||
}
|
||||
if fn, _, isFunc := funcCall(t.body); isFunc {
|
||||
for _, operand := range tokenOperands(t.body) {
|
||||
a := splitArm(operand, refs)
|
||||
if _, isBound := bound[a.key]; isBound {
|
||||
names = append(names, reader{a.name, fmt.Sprintf("%s operand %q", fn, operand)})
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
for _, a := range splitArms(t.body, refs) {
|
||||
if _, isBound := bound[a.key]; isBound {
|
||||
names = append(names, reader{a.name, "token {" + a.name + "}"})
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
return names
|
||||
}
|
||||
|
||||
// splitArms splits a token body's '|' alternatives.
|
||||
func splitArms(body string, refs map[string]refBinding) []arm {
|
||||
parts := strings.Split(body, "|")
|
||||
arms := make([]arm, len(parts))
|
||||
for i, p := range parts {
|
||||
arms[i] = splitArm(p, refs)
|
||||
}
|
||||
return arms
|
||||
}
|
||||
|
||||
// checkNoRepeatedRead rejects a bare token repeated on a held name: {w} {w} beside
|
||||
// {uppercase(w)} would read one draw twice, where {w} {w} alone draws twice. The
|
||||
// error names the single-token spelling.
|
||||
func checkNoRepeatedRead(format string, c formatOps, refs map[string]refBinding) error {
|
||||
count := map[string]int{}
|
||||
return eachToken(format, func(t ftoken) error {
|
||||
if t.kind != 'b' {
|
||||
return nil
|
||||
}
|
||||
if _, _, isFunc := funcCall(t.body); isFunc {
|
||||
return nil
|
||||
}
|
||||
for _, a := range splitArms(t.body, refs) {
|
||||
if len(a.tail) > 0 || !c.held[a.key] {
|
||||
continue
|
||||
}
|
||||
if count[a.key]++; count[a.key] > 1 {
|
||||
return fmt.Errorf("token {%s} is repeated, and %s holds %q to one draw per expansion; write {%s} once", a.name, c.holder[a.key], a.key, a.name)
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
}
|
||||
|
||||
// draws is what an expansion has already drawn for its held names: the variant each
|
||||
// was drawn as, so every path under it reads one row, and the value each read, so
|
||||
// the same name read twice reads one value.
|
||||
type draws struct {
|
||||
variant map[string]node
|
||||
value map[string]string
|
||||
}
|
||||
|
||||
// readField renders one arm of a token. An arm's key is a sibling field or a
|
||||
// reference linkRefs bound into fields. A name the expansion holds — a level some
|
||||
// token addresses by dotted path, or a field an operand reads — is drawn once and
|
||||
// kept, so {place.postal-code} and {place.locality} read one row, either read twice
|
||||
// gives one value, and a shown operand is the operand computed. Every other name is
|
||||
// drawn afresh, so {word} {word} still draws twice. checkTokens, checkPath and
|
||||
// linkRefs prove every step, so the walk cannot fail.
|
||||
func readField(s *session, t *template, held *draws, a arm) string {
|
||||
if !t.held[a.key] {
|
||||
return render(s, t.fields[a.key])
|
||||
}
|
||||
if v, read := held.value[a.name]; read {
|
||||
return v
|
||||
}
|
||||
var v string
|
||||
_ = walkPath(t.fields[a.key], a.tail, pathWalk{
|
||||
// Hold the draw at every level passed through, so two paths sharing a
|
||||
// prefix share it.
|
||||
choice: func(c *choice, rest []string) ([]node, error) {
|
||||
key := a.key
|
||||
if consumed := len(a.tail) - len(rest); consumed > 0 {
|
||||
key = a.steps[consumed-1]
|
||||
}
|
||||
n, drew := held.variant[key]
|
||||
if !drew {
|
||||
n = drawn(s, c)
|
||||
held.variant[key] = n
|
||||
}
|
||||
return []node{n}, nil
|
||||
},
|
||||
leaf: func(n node) error { v = render(s, n); return nil },
|
||||
})
|
||||
held.value[a.name] = v
|
||||
return v
|
||||
}
|
||||
|
||||
// drawn resolves a choice to one variant, so a bound head is a concrete node the
|
||||
// rest of the expansion shares. Nested choices unwrap too: a draw is one value, not
|
||||
// another set to pick from.
|
||||
func drawn(s *session, n node) node {
|
||||
for c, ok := n.(*choice); ok; c, ok = n.(*choice) {
|
||||
n = pick(s, c)
|
||||
}
|
||||
return n
|
||||
}
|
||||
@@ -149,8 +149,8 @@ func compileChoice(items []any) (node, error) {
|
||||
}
|
||||
c.cum = cum
|
||||
}
|
||||
// Safe to precompute: a choice's items come from one file, so no group can
|
||||
// appear inside one, and neither mergeChildren nor linkRefs can reach in.
|
||||
// Computed before linkRefs binds references into the items: a binding is keyed
|
||||
// by a reference sigil, which paths skips, so the set is the same after.
|
||||
c.shared = sharedPaths(c.items)
|
||||
return c, nil
|
||||
}
|
||||
@@ -229,43 +229,6 @@ func compileTemplate(m map[string]any) (node, error) {
|
||||
return t, nil
|
||||
}
|
||||
|
||||
// checkPath reports whether a token's dotted tail can address a node whichever way
|
||||
// the draw goes, by the reachability rule descend applies — a choice must carry
|
||||
// the whole remaining path in the set every variant shares — plus the
|
||||
// rules a held draw adds, which descend has no need of: a level a path reads may
|
||||
// not carry a repeat, and each variant answers for that itself. So a path that
|
||||
// validates here resolves on every render, and a typo is a New-time error.
|
||||
func checkPath(n node, tail []string, level string) error {
|
||||
if len(tail) == 0 {
|
||||
return nil
|
||||
}
|
||||
switch n := n.(type) {
|
||||
case *template:
|
||||
if n.repeat > 1 {
|
||||
return fmt.Errorf("the level %q carries a repeat, which a path reading one draw of it cannot apply", level)
|
||||
}
|
||||
child, ok := n.fields[tail[0]]
|
||||
if !ok {
|
||||
return fmt.Errorf("no field %q", tail[0])
|
||||
}
|
||||
return checkPath(child, tail[1:], level+"."+tail[0])
|
||||
case *choice:
|
||||
if want := strings.Join(tail, "."); !n.shared[want] {
|
||||
return unreachableInChoice(n, want)
|
||||
}
|
||||
// Reachability is settled; each variant still answers for itself, so a
|
||||
// rule about the level (its repeat) holds behind a choice as in front.
|
||||
for _, item := range n.items {
|
||||
if err := checkPath(item, tail, level); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
return nil
|
||||
default:
|
||||
return fmt.Errorf("cannot descend into %T at %q", n, tail[0])
|
||||
}
|
||||
}
|
||||
|
||||
// repeatOf reads a template's "repeat" (default 1): how many times its format
|
||||
// is rendered and concatenated. A present one must be an integer above 1.
|
||||
func repeatOf(m map[string]any) (int, error) {
|
||||
|
||||
@@ -0,0 +1,109 @@
|
||||
package fejkdata
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"sort"
|
||||
"strings"
|
||||
)
|
||||
|
||||
// pathWalk is what one walk of a dotted path does at each kind of level: choice
|
||||
// returns the variants to continue into (none stops the walk); level runs at each
|
||||
// template a segment descends into; leaf runs where the tail ends. A nil action
|
||||
// is skipped.
|
||||
type pathWalk struct {
|
||||
choice func(c *choice, rest []string) ([]node, error)
|
||||
level func(t *template, rest []string) error
|
||||
leaf func(n node) error
|
||||
}
|
||||
|
||||
// walkPath descends tail from n: a group or template by its next segment, a
|
||||
// choice by w.choice, which consumes no segment. A missing segment is an error,
|
||||
// so no walk reaches past what the data holds.
|
||||
func walkPath(n node, tail []string, w pathWalk) error {
|
||||
if len(tail) == 0 {
|
||||
if w.leaf != nil {
|
||||
return w.leaf(n)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
switch n := n.(type) {
|
||||
case *group:
|
||||
child, ok := n.children[tail[0]]
|
||||
if !ok {
|
||||
return fmt.Errorf("no entry %q", tail[0])
|
||||
}
|
||||
return walkPath(child, tail[1:], w)
|
||||
case *template:
|
||||
if w.level != nil {
|
||||
if err := w.level(n, tail); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
child, ok := n.fields[tail[0]]
|
||||
if !ok {
|
||||
return fmt.Errorf("no field %q", tail[0])
|
||||
}
|
||||
return walkPath(child, tail[1:], w)
|
||||
case *choice:
|
||||
if w.choice == nil {
|
||||
return nil
|
||||
}
|
||||
next, err := w.choice(n, tail)
|
||||
if err != nil {
|
||||
return err
|
||||
}
|
||||
for _, item := range next {
|
||||
if err := walkPath(item, tail, w); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
return fmt.Errorf("cannot descend into %T at %q", n, tail[0])
|
||||
}
|
||||
|
||||
// carriedByAll is the choice rule a path that must resolve on every call obeys:
|
||||
// the rest of the tail must be one every variant carries.
|
||||
func carriedByAll(c *choice, rest []string) error {
|
||||
if want := strings.Join(rest, "."); !c.shared[want] {
|
||||
return unreachableInChoice(c, want)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// unreachableInChoice reports that a path cannot step through this choice, listing
|
||||
// what every variant does carry. It reads the precomputed set, so a failing path
|
||||
// costs no more than a rendering one.
|
||||
func unreachableInChoice(c *choice, want string) error {
|
||||
if len(c.shared) == 0 {
|
||||
return fmt.Errorf("no variant of this %d-way choice carries %q", len(c.items), want)
|
||||
}
|
||||
offered := make([]string, 0, len(c.shared))
|
||||
for p := range c.shared {
|
||||
offered = append(offered, p)
|
||||
}
|
||||
sort.Strings(offered)
|
||||
return fmt.Errorf("not every variant of this %d-way choice carries %q; all carry %v", len(c.items), want, offered)
|
||||
}
|
||||
|
||||
// checkPath proves a dotted tail resolves whichever way the draws go — a choice
|
||||
// must carry the rest of the path in the set every variant shares — and that no
|
||||
// level a path reads carries a repeat, which one draw of it could not apply. So a
|
||||
// path that validates here resolves on every render, and a typo is a New-time
|
||||
// error.
|
||||
func checkPath(n node, tail []string, level string) error {
|
||||
return walkPath(n, tail, pathWalk{
|
||||
choice: func(c *choice, rest []string) ([]node, error) {
|
||||
if err := carriedByAll(c, rest); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return c.items, nil
|
||||
},
|
||||
level: func(t *template, rest []string) error {
|
||||
if t.repeat > 1 {
|
||||
return fmt.Errorf("the level %q carries a repeat, which a path reading one draw of it cannot apply", join(level, strings.Join(tail[:len(tail)-len(rest)], ".")))
|
||||
}
|
||||
return nil
|
||||
},
|
||||
})
|
||||
}
|
||||
-388
@@ -2,7 +2,6 @@ package fejkdata
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"sort"
|
||||
"strings"
|
||||
)
|
||||
|
||||
@@ -137,248 +136,6 @@ func eachTemplate(root map[string]node, fn func(folder []string, path string, t
|
||||
return inFolder(nil, root)
|
||||
}
|
||||
|
||||
// checkBoundLevelsHeld rejects every route to a held name except the ones that read
|
||||
// its draw. An expansion holds one draw of that name; anything else that renders it
|
||||
// draws again, and the two disagree. checkNoOverlap settles the spellings within one
|
||||
// format (a token, an operand); this settles the rest — a reference, whether it
|
||||
// sits in that format or in anything the format renders, however deep.
|
||||
//
|
||||
// It runs after checkNoCycles, whose guarantee is what lets the walk terminate.
|
||||
func checkBoundLevelsHeld(root map[string]node) error {
|
||||
return walkNodes(root, func(path string, n node) error {
|
||||
t, ok := n.(*template)
|
||||
if !ok || len(t.held) == 0 {
|
||||
return nil
|
||||
}
|
||||
heads := make([]string, 0, len(t.held))
|
||||
for head := range t.held {
|
||||
heads = append(heads, head)
|
||||
}
|
||||
// Operand heads first, then paths, each in name order: a level read both
|
||||
// ways is reported by the operand's fence, and which overlap is reported
|
||||
// does not vary.
|
||||
sort.Slice(heads, func(i, j int) bool {
|
||||
_, pi := t.bound[heads[i]]
|
||||
_, pj := t.bound[heads[j]]
|
||||
if pi != pj {
|
||||
return !pi
|
||||
}
|
||||
return heads[i] < heads[j]
|
||||
})
|
||||
readers := boundReaders(t.format, t.bound, t.refs)
|
||||
for _, head := range heads {
|
||||
// What one draw answers for depends on how the draw is read: a path pins
|
||||
// the levels it passes through and the leaf it lands on, an operand
|
||||
// exactly the value its render produces.
|
||||
held := map[node]bool{}
|
||||
reader, isPath := t.bound[head]
|
||||
if isPath {
|
||||
for _, r := range readers {
|
||||
if a := splitArm(r.name, t.refs); a.key == head {
|
||||
coverPath(t.fields[head], a.tail, held)
|
||||
}
|
||||
}
|
||||
} else {
|
||||
operandDraw(t.fields[head], held)
|
||||
}
|
||||
if len(held) == 0 {
|
||||
continue // an early out: a fixed head holds nothing to reach
|
||||
}
|
||||
// One seen set across the edges: a node that cannot reach the level
|
||||
// cannot reach it by another route either, so it is walked once here.
|
||||
seen := map[node]bool{}
|
||||
for _, e := range renderEdges(t) {
|
||||
if splitArm(e.label, t.refs).key == head {
|
||||
continue // a token or operand reading this draw, the routes allowed
|
||||
}
|
||||
if renders(e.to, held, seen) {
|
||||
if isPath {
|
||||
return fmt.Errorf("%s: %s renders %q, which {%s} reads a path into; name the fields you want instead", path, e.reached(), head, reader)
|
||||
}
|
||||
return fmt.Errorf("%s: %s renders %q, which a {%s()} also reads; reach it one way so it is drawn once", path, e.reached(), head, operandReader(t, head))
|
||||
}
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
}
|
||||
|
||||
// operandReader names the builtin whose operand holds head.
|
||||
func operandReader(t *template, head string) string {
|
||||
fn := ""
|
||||
_ = eachToken(t.format, func(tok ftoken) error {
|
||||
if tok.kind != 'b' || fn != "" {
|
||||
return nil
|
||||
}
|
||||
if name, _, isFunc := funcCall(tok.body); isFunc {
|
||||
for _, operand := range tokenOperands(tok.body) {
|
||||
if splitArm(operand, t.refs).key == head {
|
||||
fn = name
|
||||
}
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
return fn
|
||||
}
|
||||
|
||||
// coverPath collects what holding one path pins: every choice level the path
|
||||
// passes through, whole, and the leaf it renders.
|
||||
func coverPath(n node, tail []string, into map[node]bool) {
|
||||
if _, isChoice := n.(*choice); isChoice || len(tail) == 0 {
|
||||
cover(n, into, false)
|
||||
return
|
||||
}
|
||||
t, ok := n.(*template)
|
||||
if !ok {
|
||||
return
|
||||
}
|
||||
if child, ok := t.fields[tail[0]]; ok {
|
||||
coverPath(child, tail[1:], into)
|
||||
}
|
||||
}
|
||||
|
||||
// cover collects a level and everything contained in it. A fixed string outside a
|
||||
// choice is left out — it cannot disagree with itself — but inside one each
|
||||
// variant carries its own, so there it counts.
|
||||
func cover(n node, into map[node]bool, inChoice bool) {
|
||||
if isFixed(n) && !inChoice {
|
||||
return
|
||||
}
|
||||
into[n] = true
|
||||
_, isChoice := n.(*choice)
|
||||
for _, c := range contained(n) {
|
||||
cover(c.node, into, inChoice || isChoice)
|
||||
}
|
||||
}
|
||||
|
||||
// operandDraw collects what one held draw of an operand answers for: the operand
|
||||
// and what rendering it settles inside itself. The builtin renders its operand
|
||||
// whole, so that draw fixes every value the render produced, and a second route to
|
||||
// any of them disagrees with it.
|
||||
//
|
||||
// The walk stops at a reference edge, which is where the operand's own value ends
|
||||
// and a shared source begins: two names referencing one category are two draws, the
|
||||
// same rule {word} {word} follows.
|
||||
func operandDraw(n node, into map[node]bool) {
|
||||
if isFixed(n) {
|
||||
return
|
||||
}
|
||||
if into[n] {
|
||||
return
|
||||
}
|
||||
into[n] = true
|
||||
for _, e := range renderEdges(n) {
|
||||
if isRef(e.label) {
|
||||
continue
|
||||
}
|
||||
operandDraw(e.to, into)
|
||||
}
|
||||
}
|
||||
|
||||
// isFixed is a string that varies nothing: fixed text with no fields to read into.
|
||||
func isFixed(n node) bool {
|
||||
t, ok := n.(*template)
|
||||
return ok && t.fixed && len(t.fields) == 0
|
||||
}
|
||||
|
||||
// renders reports whether rendering n can reach anything in want, following the
|
||||
// same edges expand does. seen keeps a node shared by several routes from being
|
||||
// walked twice; checkNoCycles has already proved the graph is a DAG, so the walk
|
||||
// ends.
|
||||
func renders(n node, want, seen map[node]bool) bool {
|
||||
if want[n] {
|
||||
return true
|
||||
}
|
||||
if seen[n] {
|
||||
return false
|
||||
}
|
||||
seen[n] = true
|
||||
for _, e := range renderEdges(n) {
|
||||
if renders(e.to, want, seen) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// walkNodes calls fn once per contained node, passing the dot path that reaches it,
|
||||
// visiting keys in sorted order so which of several broken nodes gets reported does
|
||||
// not depend on map iteration.
|
||||
func walkNodes(root map[string]node, fn func(path string, n node) error) error {
|
||||
seen := map[node]bool{}
|
||||
var visit func(string, node) error
|
||||
visit = func(path string, n node) error {
|
||||
if n == nil || seen[n] {
|
||||
return nil
|
||||
}
|
||||
seen[n] = true
|
||||
if err := fn(path, n); err != nil {
|
||||
return err
|
||||
}
|
||||
for _, c := range contained(n) {
|
||||
if err := visit(join(path, c.name), c.node); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
for _, name := range sortedNames(root) {
|
||||
if err := visit(name, root[name]); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// namedNode is a contained child and the segment reaching it; a choice's items carry
|
||||
// no segment, matching how a dot path steps over a choice.
|
||||
type namedNode struct {
|
||||
name string
|
||||
node node
|
||||
}
|
||||
|
||||
func contained(n node) []namedNode {
|
||||
switch n := n.(type) {
|
||||
case *group:
|
||||
return named(n.children)
|
||||
case *choice:
|
||||
out := make([]namedNode, len(n.items))
|
||||
for i, it := range n.items {
|
||||
out[i] = namedNode{node: it}
|
||||
}
|
||||
return out
|
||||
case *template:
|
||||
return named(n.fields)
|
||||
default:
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
// named skips a bound {/path} key: it is a render edge, not containment, so using
|
||||
// it as a path segment would report a node under a path that does not reach it. Only
|
||||
// a template's fields hold bindings — loadDir skips a dot-prefixed entry, so a
|
||||
// group's children never carry the prefix — so this one skip serves both.
|
||||
func named(m map[string]node) []namedNode {
|
||||
out := make([]namedNode, 0, len(m))
|
||||
for _, name := range sortedNames(m) {
|
||||
if isRef(name) {
|
||||
continue
|
||||
}
|
||||
out = append(out, namedNode{name: name, node: m[name]})
|
||||
}
|
||||
return out
|
||||
}
|
||||
|
||||
func sortedNames(m map[string]node) []string {
|
||||
names := make([]string, 0, len(m))
|
||||
for name := range m {
|
||||
names = append(names, name)
|
||||
}
|
||||
sort.Strings(names)
|
||||
return names
|
||||
}
|
||||
|
||||
// resolveRef walks a reference path through the folders to the category it names,
|
||||
// returning that head, the node, and the tail left to read into it.
|
||||
func resolveRef(root map[string]node, segments []string) (head []string, target node, tail []string, err error) {
|
||||
@@ -413,148 +170,3 @@ func refTokens(format string) []string {
|
||||
}
|
||||
return refs
|
||||
}
|
||||
|
||||
// renderEdge is a child a node renders into, labelled by what reaches it (a field
|
||||
// name, reference, or choice index) for a readable cycle report. operand names
|
||||
// the builtin when the label is its operand rather than a token, so an error can
|
||||
// name it the way the author wrote it.
|
||||
type renderEdge struct {
|
||||
to node
|
||||
label string
|
||||
operand string
|
||||
}
|
||||
|
||||
// reached names an edge as the author spelled it, the vocabulary boundReaders uses
|
||||
// for the sibling fence.
|
||||
func (e renderEdge) reached() string {
|
||||
if e.operand != "" {
|
||||
return fmt.Sprintf("%s operand %q", e.operand, e.label)
|
||||
}
|
||||
return "{" + e.label + "}"
|
||||
}
|
||||
|
||||
// renderEdges lists the children rendering n recurses into, mirroring expand: a
|
||||
// choice's items, and a template's field/reference tokens plus its operands. A
|
||||
// group renders nothing, so it has no edges.
|
||||
func renderEdges(n node) []renderEdge {
|
||||
switch n := n.(type) {
|
||||
case *choice:
|
||||
es := make([]renderEdge, len(n.items))
|
||||
for i, it := range n.items {
|
||||
es[i] = renderEdge{to: it, label: fmt.Sprintf("[%d]", i)}
|
||||
}
|
||||
return es
|
||||
case *template:
|
||||
var es []renderEdge
|
||||
add := func(name, operand string) {
|
||||
a := splitArm(name, n.refs)
|
||||
c, ok := n.fields[a.key]
|
||||
if !ok {
|
||||
return
|
||||
}
|
||||
for _, leaf := range pathLeaves(c, a.tail) {
|
||||
es = append(es, renderEdge{leaf, name, operand})
|
||||
}
|
||||
}
|
||||
_ = eachToken(n.format, func(t ftoken) error {
|
||||
if t.kind != 'b' {
|
||||
return nil
|
||||
}
|
||||
if fn, _, isFunc := funcCall(t.body); isFunc {
|
||||
for _, operand := range tokenOperands(t.body) {
|
||||
add(operand, fn)
|
||||
}
|
||||
return nil
|
||||
}
|
||||
for _, name := range strings.Split(t.body, "|") {
|
||||
add(name, "")
|
||||
}
|
||||
return nil
|
||||
})
|
||||
return es
|
||||
default:
|
||||
return nil
|
||||
}
|
||||
}
|
||||
|
||||
// pathLeaves lists what a token's dotted tail renders. A path draws the levels it
|
||||
// passes through but renders only what it lands on, so the leaf is the edge — a
|
||||
// bare token, whose tail is empty, lands on the field itself. A choice on the way
|
||||
// contributes every variant, since any of them may be the one drawn. checkPath has
|
||||
// already proved the tail resolves in every variant, so the walk drops nothing.
|
||||
func pathLeaves(n node, tail []string) []node {
|
||||
if len(tail) == 0 {
|
||||
return []node{n}
|
||||
}
|
||||
if c, ok := n.(*choice); ok {
|
||||
var out []node
|
||||
for _, it := range c.items {
|
||||
out = append(out, pathLeaves(it, tail)...)
|
||||
}
|
||||
return out
|
||||
}
|
||||
return pathLeaves(child(n, tail[0]), tail[1:])
|
||||
}
|
||||
|
||||
// checkRepeatReach bounds the renders a repeat multiplies to along any root-to-leaf
|
||||
// path, so nested repeats cannot build what one repeat may not. It runs after
|
||||
// checkNoCycles, whose guarantee is what lets the walk terminate.
|
||||
func checkRepeatReach(root map[string]node) error {
|
||||
reach := map[node]int{}
|
||||
var of func(n node) int
|
||||
of = func(n node) int {
|
||||
if r, done := reach[n]; done {
|
||||
return r
|
||||
}
|
||||
r := 1
|
||||
for _, e := range renderEdges(n) {
|
||||
if c := of(e.to); c > r {
|
||||
r = c
|
||||
}
|
||||
}
|
||||
if t, ok := n.(*template); ok {
|
||||
r *= t.repeat
|
||||
}
|
||||
reach[n] = r
|
||||
return r
|
||||
}
|
||||
return walkNodes(root, func(path string, n node) error {
|
||||
if t, ok := n.(*template); ok && t.repeat > 1 && of(n) > maxLen {
|
||||
return fmt.Errorf("%s: repeat %d multiplies to %d renders along one path, above the maximum %d", path, t.repeat, of(n), maxLen)
|
||||
}
|
||||
return nil
|
||||
})
|
||||
}
|
||||
|
||||
// checkNoCycles rejects a reference cycle: a node whose rendering can reach itself
|
||||
// — directly, mutually, or through a chain — never terminates, so it must fail at
|
||||
// New rather than stack-overflow at render. It is a depth-first walk of the render
|
||||
// graph (renderEdges); grey marks nodes on the current path so a back-edge to one
|
||||
// is the cycle, while black lets a shared node (a DAG, not a cycle) be skipped.
|
||||
// Every node is a root: a field its parent's format never renders is still reachable
|
||||
// by dot path, so a cycle in one would otherwise reach render and be fatal there.
|
||||
func checkNoCycles(root map[string]node) error {
|
||||
const (
|
||||
grey = 1
|
||||
black = 2
|
||||
)
|
||||
color := map[node]int{}
|
||||
var visit func(n node, path string) error
|
||||
visit = func(n node, path string) error {
|
||||
switch color[n] {
|
||||
case grey:
|
||||
return fmt.Errorf("reference cycle: %s", path)
|
||||
case black:
|
||||
return nil
|
||||
}
|
||||
color[n] = grey
|
||||
for _, e := range renderEdges(n) {
|
||||
if err := visit(e.to, path+" -> "+e.label); err != nil {
|
||||
return err
|
||||
}
|
||||
}
|
||||
color[n] = black
|
||||
return nil
|
||||
}
|
||||
return walkNodes(root, func(path string, n node) error { return visit(n, path) })
|
||||
}
|
||||
|
||||
@@ -33,48 +33,20 @@ func (f *Generator) Fake(path string) (string, error) {
|
||||
// descend walks named fields to the node a path names. It is the one render-side
|
||||
// step that can fail, because the path comes from the caller and may name a field
|
||||
// that does not exist. A choice consumes no segment, so the rest of the path must
|
||||
// be one every variant carries (the set compile stored) before a variant is picked
|
||||
// — a path that resolves at all resolves on every call.
|
||||
func descend(s *session, n node, segments []string) (node, error) {
|
||||
if len(segments) == 0 {
|
||||
return n, nil
|
||||
}
|
||||
switch n := n.(type) {
|
||||
case *group:
|
||||
child, ok := n.children[segments[0]]
|
||||
if !ok {
|
||||
return nil, fmt.Errorf("no entry %q", segments[0])
|
||||
}
|
||||
return descend(s, child, segments[1:])
|
||||
case *template:
|
||||
child, ok := n.fields[segments[0]]
|
||||
if !ok {
|
||||
return nil, fmt.Errorf("no field %q", segments[0])
|
||||
}
|
||||
return descend(s, child, segments[1:])
|
||||
case *choice:
|
||||
if want := strings.Join(segments, "."); !n.shared[want] {
|
||||
return nil, unreachableInChoice(n, want)
|
||||
}
|
||||
return descend(s, pick(s, n), segments)
|
||||
default:
|
||||
return nil, fmt.Errorf("cannot descend into %T at %q", n, segments[0])
|
||||
}
|
||||
}
|
||||
|
||||
// unreachableInChoice reports that a path cannot step through this choice, listing
|
||||
// what every variant does carry. It reads the precomputed set, so a failing path
|
||||
// costs no more than a rendering one.
|
||||
func unreachableInChoice(c *choice, want string) error {
|
||||
if len(c.shared) == 0 {
|
||||
return fmt.Errorf("no variant of this %d-way choice carries %q", len(c.items), want)
|
||||
}
|
||||
offered := make([]string, 0, len(c.shared))
|
||||
for p := range c.shared {
|
||||
offered = append(offered, p)
|
||||
}
|
||||
sort.Strings(offered)
|
||||
return fmt.Errorf("not every variant of this %d-way choice carries %q; all carry %v", len(c.items), want, offered)
|
||||
// be one every variant carries before a variant is picked — a path that resolves
|
||||
// at all resolves on every call.
|
||||
func descend(s *session, root node, segments []string) (node, error) {
|
||||
var found node
|
||||
err := walkPath(root, segments, pathWalk{
|
||||
choice: func(c *choice, rest []string) ([]node, error) {
|
||||
if err := carriedByAll(c, rest); err != nil {
|
||||
return nil, err
|
||||
}
|
||||
return []node{pick(s, c)}, nil
|
||||
},
|
||||
leaf: func(n node) error { found = n; return nil },
|
||||
})
|
||||
return found, err
|
||||
}
|
||||
|
||||
// render evaluates a compiled node to a string. compile validates every node up
|
||||
@@ -152,76 +124,3 @@ func expand(s *session, t *template) string {
|
||||
}
|
||||
return b.String()
|
||||
}
|
||||
|
||||
// draws is what an expansion has already drawn for its held names: the variant each
|
||||
// was drawn as, so every path under it reads one row, and the value each read, so
|
||||
// the same name read twice reads one value.
|
||||
type draws struct {
|
||||
variant map[string]node
|
||||
value map[string]string
|
||||
}
|
||||
|
||||
// readField renders one arm of a token. An arm's key is a sibling field or a
|
||||
// {/path} reference, which linkRefs bound into fields too. A name the expansion
|
||||
// holds — a level some token addresses by dotted path, or a sibling a {calc()}
|
||||
// reads — is drawn once and kept, so {place.postal-code} and {place.locality} read
|
||||
// one row, either read twice gives one value, and a shown operand is the operand
|
||||
// computed. Every other name is drawn afresh, so {word} {word} still draws twice.
|
||||
// checkTokens, checkPath and linkRefs prove every step, so this cannot fail.
|
||||
func readField(s *session, t *template, held *draws, a arm) string {
|
||||
if !t.held[a.key] {
|
||||
return render(s, t.fields[a.key])
|
||||
}
|
||||
if v, read := held.value[a.name]; read {
|
||||
return v
|
||||
}
|
||||
n, drew := held.variant[a.key]
|
||||
if !drew {
|
||||
n = drawn(s, t.fields[a.key])
|
||||
held.variant[a.key] = n
|
||||
}
|
||||
// Hold the draw at every level passed through, so two paths sharing a prefix
|
||||
// share it.
|
||||
for i, seg := range a.tail {
|
||||
if i < len(a.steps) {
|
||||
step, drew := held.variant[a.steps[i]]
|
||||
if !drew {
|
||||
step = drawn(s, child(n, seg))
|
||||
held.variant[a.steps[i]] = step
|
||||
}
|
||||
n = step
|
||||
continue
|
||||
}
|
||||
n = child(n, seg)
|
||||
}
|
||||
v := render(s, n)
|
||||
held.value[a.name] = v
|
||||
return v
|
||||
}
|
||||
|
||||
// child is the node one path segment names below an already-drawn node. It holds
|
||||
// while checkPath and the set a choice shares (see sharedPaths) agree with this
|
||||
// walk: both prove the segment exists and that drawn leaves a template here. Each
|
||||
// way that can break panics naming the segment, so a slip in that agreement
|
||||
// reports where it happened rather than surfacing a nil node a level later.
|
||||
func child(n node, seg string) node {
|
||||
t, ok := n.(*template)
|
||||
if !ok {
|
||||
panic(fmt.Sprintf("fejkdata: %q under %T, which carries no fields", seg, n))
|
||||
}
|
||||
c, ok := t.fields[seg]
|
||||
if !ok {
|
||||
panic(fmt.Sprintf("fejkdata: no field %q under a drawn level", seg))
|
||||
}
|
||||
return c
|
||||
}
|
||||
|
||||
// drawn resolves a choice to one variant, so a bound head is a concrete node the
|
||||
// rest of the expansion shares. Nested choices unwrap too: a draw is one value, not
|
||||
// another set to pick from.
|
||||
func drawn(s *session, n node) node {
|
||||
for c, ok := n.(*choice); ok; c, ok = n.(*choice) {
|
||||
n = pick(s, c)
|
||||
}
|
||||
return n
|
||||
}
|
||||
|
||||
-127
@@ -2,7 +2,6 @@ package fejkdata
|
||||
|
||||
import (
|
||||
"fmt"
|
||||
"sort"
|
||||
"strings"
|
||||
)
|
||||
|
||||
@@ -229,98 +228,6 @@ func fieldTokens(format string) []string {
|
||||
return names
|
||||
}
|
||||
|
||||
// arm is one alternative of a {a|b} token or one operand, split into the key
|
||||
// naming the node in a template's fields (a sibling field, or the head a
|
||||
// reference is bound under) and the tail of a dotted path into it. A non-empty
|
||||
// tail is what makes the arm a bound draw: its head is drawn once per expansion
|
||||
// (see compileOps).
|
||||
type arm struct {
|
||||
name string // as written, and the key a bound draw's value is held under
|
||||
key string
|
||||
tail []string
|
||||
steps []string // key per level passed through; the head and leaf hold their own
|
||||
}
|
||||
|
||||
// splitArm splits one name into key and tail. refs maps a reference to what
|
||||
// linkRefs bound it to; before linking, a reference is whole.
|
||||
func splitArm(name string, refs map[string]refBinding) arm {
|
||||
if isRef(name) {
|
||||
b, bound := refs[name]
|
||||
if !bound || len(b.tail) == 0 {
|
||||
key := name
|
||||
if bound {
|
||||
key = b.key
|
||||
}
|
||||
return arm{name: name, key: key}
|
||||
}
|
||||
return pathArm(name, b.key, b.tail)
|
||||
}
|
||||
head, tail, dotted := strings.Cut(name, ".")
|
||||
if !dotted {
|
||||
return arm{name: name, key: name}
|
||||
}
|
||||
return pathArm(name, head, strings.Split(tail, "."))
|
||||
}
|
||||
|
||||
func pathArm(name, key string, segs []string) arm {
|
||||
var steps []string
|
||||
for i := 0; i < len(segs)-1; i++ { // every level except the leaf's own
|
||||
steps = append(steps, key+"."+strings.Join(segs[:i+1], "."))
|
||||
}
|
||||
return arm{name: name, key: key, tail: segs, steps: steps}
|
||||
}
|
||||
|
||||
// checkNoOverlap rejects a format that both renders a level and reads a path into
|
||||
// it — {p} beside {p.first}, or {p.addr} beside {p.addr.city}. The path reads the
|
||||
// level's held draw while rendering the level expands it afresh, so their values
|
||||
// would disagree. Names are compared in sorted order, so which pair is reported
|
||||
// does not depend on where the tokens sit.
|
||||
func checkNoOverlap(format string, bound map[string]string, refs map[string]refBinding) error {
|
||||
names := boundReaders(format, bound, refs)
|
||||
// Stable over one format-order scan, so two readers of one name (a token and a
|
||||
// calc operand both naming "p") are reported as the format writes them.
|
||||
sort.SliceStable(names, func(i, j int) bool { return names[i].name < names[j].name })
|
||||
for i, level := range names {
|
||||
for _, path := range names[i+1:] {
|
||||
if strings.HasPrefix(path.name, level.name+".") {
|
||||
return fmt.Errorf("%s renders a level that {%s} reads a path into; name the fields you want instead", level.label, path.name)
|
||||
}
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
|
||||
// reader is one way a format reaches a bound field, and how to name that spelling.
|
||||
type reader struct{ name, label string }
|
||||
|
||||
// boundReaders lists every way a format reaches a bound field, in the order the
|
||||
// format writes them. An operand renders its field, so it names a level exactly
|
||||
// as a token does; one scan finds both, which is what puts them in one order.
|
||||
func boundReaders(format string, bound map[string]string, refs map[string]refBinding) []reader {
|
||||
var names []reader
|
||||
_ = eachToken(format, func(t ftoken) error {
|
||||
if t.kind != 'b' {
|
||||
return nil
|
||||
}
|
||||
if fn, _, isFunc := funcCall(t.body); isFunc {
|
||||
for _, operand := range tokenOperands(t.body) {
|
||||
a := splitArm(operand, refs)
|
||||
if _, isBound := bound[a.key]; isBound {
|
||||
names = append(names, reader{a.name, fmt.Sprintf("%s operand %q", fn, operand)})
|
||||
}
|
||||
}
|
||||
return nil
|
||||
}
|
||||
for _, a := range splitArms(t.body, refs) {
|
||||
if _, isBound := bound[a.key]; isBound {
|
||||
names = append(names, reader{a.name, "token {" + a.name + "}"})
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
return names
|
||||
}
|
||||
|
||||
// checkSegments rejects an unfinished path: "{a.}", "{.b}" and "{a..b}" each have
|
||||
// a segment naming nothing. A field really named "" would otherwise make them
|
||||
// resolve, so a typo would read as a path that worked.
|
||||
@@ -339,16 +246,6 @@ func checkSegments(a arm) error {
|
||||
return nil
|
||||
}
|
||||
|
||||
// splitArms splits a token body's '|' alternatives.
|
||||
func splitArms(body string, refs map[string]refBinding) []arm {
|
||||
parts := strings.Split(body, "|")
|
||||
arms := make([]arm, len(parts))
|
||||
for i, p := range parts {
|
||||
arms[i] = splitArm(p, refs)
|
||||
}
|
||||
return arms
|
||||
}
|
||||
|
||||
// callFn is a builtin bound to one call site: its args already parsed. It reads the
|
||||
// output emitted so far in the current expansion (a derivation's payload) and the
|
||||
// values of the operands it named, which expand read for it.
|
||||
@@ -450,27 +347,3 @@ func compileOps(format string, refs map[string]refBinding) formatOps {
|
||||
flush()
|
||||
return c
|
||||
}
|
||||
|
||||
// checkNoRepeatedRead rejects a bare token repeated on a held name: {w} {w} beside
|
||||
// {uppercase(w)} would read one draw twice, where {w} {w} alone draws twice. The
|
||||
// error names the single-token spelling.
|
||||
func checkNoRepeatedRead(format string, c formatOps, refs map[string]refBinding) error {
|
||||
count := map[string]int{}
|
||||
return eachToken(format, func(t ftoken) error {
|
||||
if t.kind != 'b' {
|
||||
return nil
|
||||
}
|
||||
if _, _, isFunc := funcCall(t.body); isFunc {
|
||||
return nil
|
||||
}
|
||||
for _, a := range splitArms(t.body, refs) {
|
||||
if len(a.tail) > 0 || !c.held[a.key] {
|
||||
continue
|
||||
}
|
||||
if count[a.key]++; count[a.key] > 1 {
|
||||
return fmt.Errorf("token {%s} is repeated, and %s holds %q to one draw per expansion; write {%s} once", a.name, c.holder[a.key], a.key, a.name)
|
||||
}
|
||||
}
|
||||
return nil
|
||||
})
|
||||
}
|
||||
|
||||
Reference in New Issue
Block a user