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Format text is literal; class runs are {digits(n)} {upper(n)} {lower(n)}; a string is a format

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Lilleman auf Larv
2026-09-02 12:37:21 +02:00
parent 99d8aa0fb7
commit ff4b243148
29 changed files with 308 additions and 267 deletions
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builtins.go
+27 -35
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@@ -16,27 +16,21 @@ const (
maxDecimals = 1024
)
// builtins is the registry of {name(args)} functions. Derivations read the
// digits emitted so far in the current expansion (luhn, mod11, ean — place them
// after their payload); samples read only the rng (uuid, ulid, ...). All
// must stay pure over (rng, emitted, args) so seeded output is reproducible — a
// time-based id (uuid v7, ulid) draws its timestamp from the rng, not the wall
// clock. Add a builtin only for what data can't express: a random v4 UUID and a
// 24-hex ObjectID both ship as data, so the uuid builtin is v7.
// builtins is the registry of {name(args)} functions. Derivations read the digits
// emitted so far in the current expansion (place them after their payload);
// samples read only the rng. A time-based id (uuid v7, ulid) draws its timestamp
// from the rng, not the wall clock, so seeded output stays reproducible.
var builtins = map[string]builtin{
"luhn": {arity: 0, prep: derive(func(e string) string { return string(rune('0' + luhnCheck(e))) })},
"mod11": {arity: 0, prep: derive(mod11Check)},
"ean": {arity: 0, prep: derive(eanCheck)},
"uuid": {arity: 0, prep: sample(uuidV7)},
"ulid": {arity: 0, prep: sample(ulid)},
"nanoid": {arity: 1, check: posIntArg, prep: func(a []string) callFn {
n := atoi(a[0])
return func(s *session, _ string, _ []string) string { return nanoid(s, n) }
}},
"hex": {arity: 1, check: posIntArg, prep: func(a []string) callFn {
n := atoi(a[0])
return func(s *session, _ string, _ []string) string { return randHex(s, n) }
}},
"luhn": {arity: 0, prep: derive(func(e string) string { return string(rune('0' + luhnCheck(e))) })},
"mod11": {arity: 0, prep: derive(mod11Check)},
"ean": {arity: 0, prep: derive(eanCheck)},
"uuid": {arity: 0, prep: sample(uuidV7)},
"ulid": {arity: 0, prep: sample(ulid)},
"nanoid": {arity: 1, check: posIntArg, prep: chars(nanoidAlphabet)},
"hex": {arity: 1, check: posIntArg, prep: chars(hexDigits)},
"digits": {arity: 1, check: posIntArg, prep: chars("0123456789")},
"upper": {arity: 1, check: posIntArg, prep: chars("ABCDEFGHIJKLMNOPQRSTUVWXYZ")},
"lower": {arity: 1, check: posIntArg, prep: chars("abcdefghijklmnopqrstuvwxyz")},
"base64": {arity: 1, check: posIntArg, prep: func(a []string) callFn {
n := atoi(a[0])
return func(s *session, _ string, _ []string) string {
@@ -74,9 +68,9 @@ var builtins = map[string]builtin{
}},
}
// derive and sample are the two argument-free builtin shapes the README names: a
// derivation reads the output emitted so far, a sample reads only the rng. Each
// lifts that one function into the prep every registry entry supplies.
// derive and sample are the two argument-free builtin shapes: a derivation reads
// the output emitted so far, a sample reads only the rng. chars is the shape of a
// sample of n characters drawn from an alphabet.
func derive(f func(emitted string) string) func([]string) callFn {
return func([]string) callFn {
return func(_ *session, emitted string, _ []string) string { return f(emitted) }
@@ -89,6 +83,13 @@ func sample(f func(rng) string) func([]string) callFn {
}
}
func chars(alphabet string) func([]string) callFn {
return func(a []string) callFn {
n := atoi(a[0])
return func(s *session, _ string, _ []string) string { return randChars(s, n, alphabet) }
}
}
const hexDigits = "0123456789abcdef"
// atoi parses an arg a builtin's check already validated. It panics rather than
@@ -119,10 +120,10 @@ func randBytes(r rng, n int) []byte {
return b
}
func randHex(r rng, n int) string {
func randChars(r rng, n int, alphabet string) string {
b := make([]byte, n)
for i := range b {
b[i] = hexDigits[r.IntN(16)]
b[i] = alphabet[r.IntN(len(alphabet))]
}
return string(b)
}
@@ -182,18 +183,9 @@ func seqArg(_ map[string]node, a []string) error {
return nil
}
// nanoidAlphabet is the 64-char URL-safe set Nano IDs use (order is irrelevant
// to the uniform pick).
// nanoidAlphabet is the 64-char URL-safe set Nano IDs use.
const nanoidAlphabet = "_-0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ"
func nanoid(r rng, n int) string {
b := make([]byte, n)
for i := range b {
b[i] = nanoidAlphabet[r.IntN(len(nanoidAlphabet))]
}
return string(b)
}
// uuidV7 builds an RFC 9562 v7 UUID. The 48-bit timestamp field is drawn from
// the rng (not the clock) to stay reproducible, then the version (7) and variant
// (10) bits are forced; the rest is random.