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Add session-scoped seq() builtin; move uuid v4 from locales to misc only

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This commit is contained in:
lilleman
2026-06-09 01:52:39 +02:00
parent ae41e6bb97
commit cde56b7924
9 changed files with 124 additions and 66 deletions
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template.go
+28 -25
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@@ -70,7 +70,7 @@ func (f *Fakes) Fake(path string) (string, error) {
// descend walks named fields, resolving choices it meets along the way. 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.
func descend(r rng, n node, segments []string) (node, error) {
func descend(s *session, n node, segments []string) (node, error) {
if len(segments) == 0 {
return n, nil
}
@@ -80,15 +80,15 @@ func descend(r rng, n node, segments []string) (node, error) {
if !ok {
return nil, fmt.Errorf("no entry %q", segments[0])
}
return descend(r, child, segments[1:])
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(r, child, segments[1:])
return descend(s, child, segments[1:])
case *choice:
return descend(r, pick(r, n), segments) // a choice consumes no path segment
return descend(s, pick(s, n), segments) // a choice consumes no path segment
default:
return nil, fmt.Errorf("cannot descend into %T at %q", n, segments[0])
}
@@ -96,22 +96,22 @@ func descend(r rng, n node, segments []string) (node, error) {
// render evaluates a compiled node to a string. compile validates every node up
// front, so rendering a compiled tree cannot fail.
func render(r rng, n node) string {
func render(s *session, n node) string {
switch n := n.(type) {
case literal:
return string(n)
case *choice:
return render(r, pick(r, n))
return render(s, pick(s, n))
case *template:
if n.repeat == 1 {
return expand(r, n.format, n.fields)
return expand(s, n.format, n.fields)
}
var b strings.Builder
for i := 0; i < n.repeat; i++ {
if i > 0 {
b.WriteString(n.separator)
}
b.WriteString(expand(r, n.format, n.fields))
b.WriteString(expand(s, n.format, n.fields))
}
return b.String()
default:
@@ -137,7 +137,7 @@ func pick(r rng, c *choice) node {
// any other "{token}" is substituted via resolve; every other rune is literal.
// checkTokens validated the braces and tokens at compile time, so this scan
// cannot fail.
func expand(r rng, format string, fields map[string]node) string {
func expand(s *session, format string, fields map[string]node) string {
var b strings.Builder
rs := []rune(format)
for i := 0; i < len(rs); i++ {
@@ -149,13 +149,13 @@ func expand(r rng, format string, fields map[string]node) string {
b.WriteRune('#')
}
case '0':
b.WriteByte(byte('0' + r.IntN(10)))
b.WriteByte(byte('0' + s.IntN(10)))
case '1':
b.WriteByte(byte('1' + r.IntN(9)))
b.WriteByte(byte('1' + s.IntN(9)))
case 'A':
b.WriteByte(byte('A' + r.IntN(26)))
b.WriteByte(byte('A' + s.IntN(26)))
case 'a':
b.WriteByte(byte('a' + r.IntN(26)))
b.WriteByte(byte('a' + s.IntN(26)))
case '{':
end := i + 1
for rs[end] != '}' { // checkTokens guarantees a closing '}'
@@ -163,9 +163,9 @@ func expand(r rng, format string, fields map[string]node) string {
}
body := string(rs[i+1 : end])
if name, args, ok := funcCall(body); ok {
b.WriteString(builtins[name].call(r, b.String(), args)) // b.String() is the output so far
b.WriteString(builtins[name].call(s, b.String(), args)) // b.String() is the output so far
} else {
b.WriteString(resolve(r, body, fields))
b.WriteString(resolve(s, body, fields))
}
i = end
default:
@@ -178,22 +178,25 @@ func expand(r rng, format string, fields map[string]node) string {
// resolve renders a "{token}" body: one or more names separated by '|', one
// picked at random. A name is a sibling field or a {..path} reference, which
// linkRefs bound into fields too; checkTokens and linkRefs guarantee both exist.
func resolve(r rng, token string, fields map[string]node) string {
func resolve(s *session, token string, fields map[string]node) string {
names := strings.Split(token, "|")
return render(r, fields[names[r.IntN(len(names))]])
return render(s, fields[names[s.IntN(len(names))]])
}
// builtin is a format-string function invoked as {name(args)}. It receives the
// rng, the output emitted so far in the current expansion (for derivations such
// as a checksum over preceding digits), and its args. A builtin must be pure
// over those inputs — no wall-clock, no crypto/rand — so seeding stays
// reproducible; a time-based id derives its time from the rng. The optional
// check validates args at compile time (their values, beyond the arity count).
// The registry lives in builtins.go.
// session (its rng, and the {seq()} counters), the output emitted so far in the
// current expansion (for derivations such as a checksum over preceding digits),
// and its args. Almost all are pure over (rng, emitted, args) — no wall-clock, no
// crypto/rand — so seeding stays reproducible; a time-based id derives its time
// from the rng. seq is the one exception: it advances per-session counter state,
// which is itself deterministic (1, 2, 3 …). arity is the exact arg count, or -1
// for variadic (then check does all the validation). The optional check validates
// args at compile time (their values, beyond the count). The registry lives in
// builtins.go.
type builtin struct {
arity int
check func(args []string) error
call func(r rng, emitted string, args []string) string
call func(s *session, emitted string, args []string) string
}
// funcCall splits a "{token}" body shaped name(args) into its parts; ok is false
@@ -230,7 +233,7 @@ func checkFunc(body string) error {
if !known {
return fmt.Errorf("token {%s}: unknown function %q", body, name)
}
if len(args) != b.arity {
if b.arity >= 0 && len(args) != b.arity {
return fmt.Errorf("token {%s}: %s takes %d args, got %d", body, name, b.arity, len(args))
}
if b.check != nil {