feat(template): add token assertions and Schema.Info

commit: 6416d3eb3390fdffedc6d0d487ccfed8e7903d58
author: brice · 10d ago · 2026-10-12 15:34 UTC
committer: brice · 10d ago · 2026-10-12 16:17 UTC
parent: ee5c1ce
signature: GPG VerifiedCD88F9E564E0102646FB6077A1A07C7C7C3E349D · arch-gpg Verified for the committer email

2 files · +78 -0

A template/assert.go +68 -0

@@ -0,0 +1,68 @@
	1	+	// SPDX-License-Identifier: MIT
	2	+
	3	+	package template
	4	+
	5	+	import "fmt"
	6	+
	7	+	// TokenError is an error about a token, positioned at it. It is what the
	8	+	// Assert functions return.
	9	+	type TokenError struct {
	10	+	Token Token
	11	+	Message string
	12	+	}
	13	+
	14	+	func (e *TokenError) Error() string { return e.Message }
	15	+
	16	+	func assertErr(t Token, desc string, want string) error {
	17	+	return &TokenError{Token: t, Message: fmt.Sprintf("Unexpected type '%s' encountered while reading '%s'. The type '%s' was expected.", t.Kind(), desc, want)}
	18	+	}
	19	+
	20	+	// AssertString returns t as a string token or a [*TokenError] worded like the
	21	+	// reference's "Unexpected type 'X' encountered while reading 'desc'".
	22	+	func AssertString(t Token, desc string) (*String, error) {
	23	+	if s, ok := t.(*String); ok {
	24	+	return s, nil
	25	+	}
	26	+	return nil, assertErr(t, desc, KindString.String())
	27	+	}
	28	+
	29	+	// AssertBoolean returns t as a boolean token or a [*TokenError].
	30	+	func AssertBoolean(t Token, desc string) (*Boolean, error) {
	31	+	if s, ok := t.(*Boolean); ok {
	32	+	return s, nil
	33	+	}
	34	+	return nil, assertErr(t, desc, KindBoolean.String())
	35	+	}
	36	+
	37	+	// AssertNumber returns t as a number token or a [*TokenError].
	38	+	func AssertNumber(t Token, desc string) (*Number, error) {
	39	+	if s, ok := t.(*Number); ok {
	40	+	return s, nil
	41	+	}
	42	+	return nil, assertErr(t, desc, KindNumber.String())
	43	+	}
	44	+
	45	+	// AssertSequence returns t as a sequence token or a [*TokenError].
	46	+	func AssertSequence(t Token, desc string) (*Sequence, error) {
	47	+	if s, ok := t.(*Sequence); ok {
	48	+	return s, nil
	49	+	}
	50	+	return nil, assertErr(t, desc, KindSequence.String())
	51	+	}
	52	+
	53	+	// AssertMapping returns t as a mapping token or a [*TokenError].
	54	+	func AssertMapping(t Token, desc string) (*Mapping, error) {
	55	+	if s, ok := t.(*Mapping); ok {
	56	+	return s, nil
	57	+	}
	58	+	return nil, assertErr(t, desc, KindMapping.String())
	59	+	}
	60	+
	61	+	// AssertScalar returns t when it is neither a sequence nor a mapping, or a
	62	+	// [*TokenError].
	63	+	func AssertScalar(t Token, desc string) (Token, error) {
	64	+	if IsScalar(t) {
	65	+	return t, nil
	66	+	}
	67	+	return nil, assertErr(t, desc, "ScalarToken")
	68	+	}

@@ -0,0 +1,68 @@
	1	+	// SPDX-License-Identifier: MIT
	2	+
	3	+	package template
	4	+
	5	+	import "fmt"
	6	+
	7	+	// TokenError is an error about a token, positioned at it. It is what the
	8	+	// Assert functions return.
	9	+	type TokenError struct {
	10	+	Token Token
	11	+	Message string
	12	+	}
	13	+
	14	+	func (e *TokenError) Error() string { return e.Message }
	15	+
	16	+	func assertErr(t Token, desc string, want string) error {
	17	+	return &TokenError{Token: t, Message: fmt.Sprintf("Unexpected type '%s' encountered while reading '%s'. The type '%s' was expected.", t.Kind(), desc, want)}
	18	+	}
	19	+
	20	+	// AssertString returns t as a string token or a [*TokenError] worded like the
	21	+	// reference's "Unexpected type 'X' encountered while reading 'desc'".
	22	+	func AssertString(t Token, desc string) (*String, error) {
	23	+	if s, ok := t.(*String); ok {
	24	+	return s, nil
	25	+	}
	26	+	return nil, assertErr(t, desc, KindString.String())
	27	+	}
	28	+
	29	+	// AssertBoolean returns t as a boolean token or a [*TokenError].
	30	+	func AssertBoolean(t Token, desc string) (*Boolean, error) {
	31	+	if s, ok := t.(*Boolean); ok {
	32	+	return s, nil
	33	+	}
	34	+	return nil, assertErr(t, desc, KindBoolean.String())
	35	+	}
	36	+
	37	+	// AssertNumber returns t as a number token or a [*TokenError].
	38	+	func AssertNumber(t Token, desc string) (*Number, error) {
	39	+	if s, ok := t.(*Number); ok {
	40	+	return s, nil
	41	+	}
	42	+	return nil, assertErr(t, desc, KindNumber.String())
	43	+	}
	44	+
	45	+	// AssertSequence returns t as a sequence token or a [*TokenError].
	46	+	func AssertSequence(t Token, desc string) (*Sequence, error) {
	47	+	if s, ok := t.(*Sequence); ok {
	48	+	return s, nil
	49	+	}
	50	+	return nil, assertErr(t, desc, KindSequence.String())
	51	+	}
	52	+
	53	+	// AssertMapping returns t as a mapping token or a [*TokenError].
	54	+	func AssertMapping(t Token, desc string) (*Mapping, error) {
	55	+	if s, ok := t.(*Mapping); ok {
	56	+	return s, nil
	57	+	}
	58	+	return nil, assertErr(t, desc, KindMapping.String())
	59	+	}
	60	+
	61	+	// AssertScalar returns t when it is neither a sequence nor a mapping, or a
	62	+	// [*TokenError].
	63	+	func AssertScalar(t Token, desc string) (Token, error) {
	64	+	if IsScalar(t) {
	65	+	return t, nil
	66	+	}
	67	+	return nil, assertErr(t, desc, "ScalarToken")
	68	+	}

M template/definfo.go +10 -0


@@ -117,3 +117,13 @@ func isDigits(s string) bool {
117	117		}
118	118		return true
119	119		}
	120	+
	121	+	// Info returns the info of the schema definition called name, with the
	122	+	// contexts and functions that definition allows, or nil when there is none.
	123	+	func (s Schema) Info(name string) DefinitionInfo {
	124	+	d := s.definitions[name]
	125	+	if d == nil {
	126	+	return nil
	127	+	}
	128	+	return newDefinitionInfo(s, nil, d)
	129	+	}


@@ -117,3 +117,13 @@ func isDigits(s string) bool {
117	}	117		}
118	return true	118		return true
119	}	119		}
		120	+
		121	+	// Info returns the info of the schema definition called name, with the
		122	+	// contexts and functions that definition allows, or nil when there is none.
		123	+	func (s Schema) Info(name string) DefinitionInfo {
		124	+	d := s.definitions[name]
		125	+	if d == nil {
		126	+	return nil
		127	+	}
		128	+	return newDefinitionInfo(s, nil, d)
		129	+	}