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Add the table node: rows TSV, key and name selection, linked tables drawn consistently, and the choice-of-rows fence

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This commit is contained in:
Lilleman auf Larv
2026-09-17 12:28:46 +02:00
parent d4060e041a
commit f6b54c8ae6
20 changed files with 1517 additions and 151 deletions
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path.go
+220 -34
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@@ -6,61 +6,244 @@ import (
"strings"
)
// splitPath splits a dotted path into segments, a selector — [key or name] after a
// table's name — becoming a segment of its own, brackets kept. A dot inside a
// selector is part of the key or name.
func splitPath(path string) ([]string, error) {
segs := make([]string, 0, strings.Count(path, ".")+2*strings.Count(path, "[")+1)
start, open := 0, -1
for i := 0; i < len(path); i++ {
switch path[i] {
case '[':
if err := checkOpen(path, i, start, open); err != nil {
return nil, err
}
segs = append(segs, path[start:i])
start, open = i, i
case ']':
if err := checkClose(path, i, open); err != nil {
return nil, err
}
segs = append(segs, path[start:i+1])
start, open = i+2, -1
i++
case '.':
if open < 0 {
segs = append(segs, path[start:i])
start = i + 1
}
}
}
if open >= 0 {
return nil, fmt.Errorf(`%q opens a selector with "[" and never closes it with "]"`, path)
}
if start <= len(path) {
segs = append(segs, path[start:])
}
return segs, nil
}
// checkOpen refuses a "[" at i that opens no selector: one inside a selector, or one
// following no name.
func checkOpen(path string, i, start, open int) error {
switch {
case open >= 0:
return fmt.Errorf(`%q holds a "[" inside a selector, which no key or name may`, path)
case i == 0:
return fmt.Errorf(`%q starts with "["; a path starts with a name, and a selector follows a table's name`, path)
case i == start:
return fmt.Errorf(`%q: a selector follows its table's name; write %s`, path, path[:i-1]+path[i:])
}
return nil
}
// checkClose refuses a "]" at i that closes no selector, closes an empty one, or is
// followed by anything but a dot or the end.
func checkClose(path string, i, open int) error {
switch {
case open < 0:
return fmt.Errorf(`%q holds a "]" that closes no "["`, path)
case i == open+1:
return fmt.Errorf("%q holds an empty selector; a selector names a row by key or name", path)
case i+1 < len(path) && path[i+1] != '.':
return fmt.Errorf(`%q: a "]" ends its selector, so a dot or the end must follow it`, path)
}
return nil
}
// indexOutside is the first c in s outside a [selector], or -1.
func indexOutside(s string, c byte) int {
depth := 0
for i := 0; i < len(s); i++ {
switch {
case s[i] == '[':
depth++
case s[i] == ']' && depth > 0:
depth--
case s[i] == c && depth == 0:
return i
}
}
return -1
}
// splitOutside splits s on c outside any [selector].
func splitOutside(s string, c byte) []string {
var parts []string
for {
i := indexOutside(s, c)
if i < 0 {
return append(parts, s)
}
parts, s = append(parts, s[:i]), s[i+1:]
}
}
// isSelector reports whether a segment is a [key or name] rather than a name.
func isSelector(seg string) bool { return strings.HasPrefix(seg, "[") }
// selectorOf is the key or name a selector segment holds.
func selectorOf(seg string) string { return seg[1 : len(seg)-1] }
// names is the segments of a path that are names, its selectors left out.
func names(segs []string) []string {
out := segs[:0:0]
for _, s := range segs {
if !isSelector(s) {
out = append(out, s)
}
}
return out
}
// 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.
// returns the variants to continue into (none stops the walk), and where it is nil
// the walk draws one with the pins' session, or stops; level runs at each template
// a segment descends into; leaf runs where the tail ends; pins is where the walk
// pins the table rows it selects and draws, nil skipping tables. A nil action is
// skipped. A render's walk sets only pins, so it allocates nothing.
type pathWalk struct {
choice func(c *choice, rest []string) ([]node, error)
level func(t *template, rest []string) error
leaf func(n node) error
pins *draws
}
// walkPath descends tail from n: a folder 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. A table-shaped dispatch, one case
// per node kind, kept whole on purpose.
func walkPath(n node, tail []string, w pathWalk) error {
// walkPath descends tail from n and returns the node it ends at: a folder or
// template by its next segment, a choice by w.choice, which consumes no segment, a
// table by walkTable. A missing segment is an error, so no walk reaches past what
// the data holds. A table-shaped dispatch, one case per node kind, kept whole on
// purpose.
func walkPath(n node, tail []string, w pathWalk) (node, error) {
if len(tail) == 0 {
if w.leaf != nil {
return w.leaf(n)
}
return nil
return n, w.atLeaf(n)
}
if t, isTable := n.(*table); isTable {
return walkTable(t, tail, w, false)
}
if isSelector(tail[0]) {
return nil, fmt.Errorf("%s is not a table, so it has no row to select", selectorOf(tail[0]))
}
switch n := n.(type) {
case *folder:
child, ok := n.children[tail[0]]
if !ok {
return fmt.Errorf("no entry %q", tail[0])
return nil, 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
return nil, err
}
}
child, ok := n.field(tail[0])
if !ok {
return fmt.Errorf("no field %q", tail[0])
return nil, 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 walkChoice(n, tail, w)
case *column:
return nil, fmt.Errorf("no field %q: %q is a column, and a cell holds no fields", tail[0], n.t.columns[n.i])
}
return fmt.Errorf("no field %q", tail[0])
return nil, fmt.Errorf("no field %q", tail[0])
}
func (w pathWalk) atLeaf(n node) error {
if w.leaf != nil {
return w.leaf(n)
}
return nil
}
// walkChoice continues a walk into the variants w.choice returns, or into one drawn
// by the pins' session where the walk names no choice action.
func walkChoice(c *choice, tail []string, w pathWalk) (node, error) {
if w.choice == nil {
if w.pins == nil || w.pins.s == nil {
return nil, nil
}
if err := carriedByAll(c, tail); err != nil {
return nil, err
}
return walkPath(pick(w.pins.s, c), tail, w)
}
next, err := w.choice(c, tail)
if err != nil {
return nil, err
}
var last node
for _, item := range next {
if last, err = walkPath(item, tail, w); err != nil {
return nil, err
}
}
return last, nil
}
// walkTable descends tail from a table: a selector first, then a column or a
// linked table by name. The walk reads a row wherever a segment follows or the
// table was reached from another; a table reached whole, with no selector, is left
// to a render's own draw.
func walkTable(t *table, tail []string, w pathWalk, descended bool) (node, error) {
sel := ""
if len(tail) > 0 && isSelector(tail[0]) {
sel, tail = selectorOf(tail[0]), tail[1:]
if len(tail) > 0 && isSelector(tail[0]) {
return nil, fmt.Errorf("%s[%s] is selected twice; one selector names its row", t.category, sel)
}
}
if w.pins != nil {
if err := readRow(w.pins, t, sel, descended || len(tail) > 0); err != nil {
return nil, err
}
}
if len(tail) == 0 {
if sel == "" && !descended {
return walkPath(t, nil, w)
}
return walkPath(t.whole, nil, w)
}
if i, ok := t.col[tail[0]]; ok {
return walkPath(t.fields[t.columns[i]], tail[1:], w)
}
if child := t.descendant(tail[0]); child != nil {
return walkTable(child, tail[1:], w, true)
}
return nil, fmt.Errorf("no column or linked table %q in %s", tail[0], t.category)
}
// readRow pins the row a path reads of t: the one its selector names, or, where the
// walk draws, one drawn where the path reads into the table.
func readRow(d *draws, t *table, sel string, draw bool) error {
if sel != "" {
return d.selectRow(t, sel)
}
if draw && d.s != nil {
d.rowOf(t)
}
return nil
}
// carriedByAll is the choice rule a path that must resolve on every call obeys:
@@ -88,12 +271,13 @@ func unreachableInChoice(c *choice, want string) error {
}
// 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 or a drawGroup, 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.
// must carry the rest of the path in the set every variant shares, a selector must
// name one row inside the rows selected before it — and that no level a path reads
// carries a repeat or a drawGroup, 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{
var pins draws
_, err := walkPath(n, tail, pathWalk{
choice: func(c *choice, rest []string) ([]node, error) {
if err := carriedByAll(c, rest); err != nil {
return nil, err
@@ -110,5 +294,7 @@ func checkPath(n node, tail []string, level string) error {
}
return nil
},
pins: &pins,
})
return err
}