From 086b851bb82fa5a8429b4bb99d82986462f0b641 Mon Sep 17 00:00:00 2001
From: apstndb <803393+apstndb@users.noreply.github.com>
Date: Mon, 25 May 2026 03:42:08 +0900
Subject: [PATCH] feat: expose ParseSchemaType

---
 ast/ast.go            |  1 +
 parse_helpers.go      |  6 ++++++
 parse_helpers_test.go | 13 +++++++++++++
 parser.go             | 23 +++++++++++++++++++++++
 4 files changed, 43 insertions(+)

diff --git a/ast/ast.go b/ast/ast.go
index 6fa26736..e012e818 100644
--- a/ast/ast.go
+++ b/ast/ast.go
@@ -528,6 +528,7 @@ func (SizedSchemaType) isSchemaType()  {}
 func (ArraySchemaType) isSchemaType()  {}
 func (StructType) isSchemaType()       {}
 func (NamedType) isSchemaType()        {}
+func (BadType) isSchemaType()          {}
 
 // IndexAlteration represents ALTER INDEX action.
 type IndexAlteration interface {
diff --git a/parse_helpers.go b/parse_helpers.go
index 6eaafed2..acd51ae4 100644
--- a/parse_helpers.go
+++ b/parse_helpers.go
@@ -43,6 +43,12 @@ func ParseType(filepath, s string) (ast.Type, error) {
 	return newParser(filepath, s).ParseType()
 }
 
+// ParseSchemaType parses an input string containing a schema type.
+// filepath can be empty, it is only used in error message.
+func ParseSchemaType(filepath, s string) (ast.SchemaType, error) {
+	return newParser(filepath, s).ParseSchemaType()
+}
+
 // ParseDDL parses an input string containing a DDL statement.
 // filepath can be empty, it is only used in error message.
 func ParseDDL(filepath, s string) (ast.DDL, error) {
diff --git a/parse_helpers_test.go b/parse_helpers_test.go
index 490e5ee6..1f3bb49c 100644
--- a/parse_helpers_test.go
+++ b/parse_helpers_test.go
@@ -70,6 +70,19 @@ func ExampleParseType() {
 	// Output:
 	// ARRAY<STRUCT<n INT64, s STRING>>
 }
+
+func ExampleParseSchemaType() {
+	typ, err := memefish.ParseSchemaType("", "ARRAY<STRING(MAX)>")
+	if err != nil {
+		panic(err)
+	}
+
+	fmt.Println(typ.SQL())
+
+	// Output:
+	// ARRAY<STRING(MAX)>
+}
+
 func ExampleParseDDL() {
 	sql := heredoc.Doc(`
 		CREATE TABLE foo (
diff --git a/parser.go b/parser.go
index 4ced5189..4111faf7 100644
--- a/parser.go
+++ b/parser.go
@@ -137,6 +137,29 @@ func (p *Parser) ParseType() (ast.Type, error) {
 	return t, nil
 }
 
+// ParseSchemaType parses a schema type.
+func (p *Parser) ParseSchemaType() (t ast.SchemaType, err error) {
+	p.nextToken()
+	l := p.Clone()
+	defer func() {
+		if r := recover(); r != nil {
+			t = p.handleParseTypeError(r, l)
+		}
+		if len(p.errors) > 0 {
+			// Reset the errors and allow processing to continue
+			err = MultiError(p.errors)
+			p.errors = nil
+		}
+	}()
+
+	t = p.parseSchemaType()
+	if p.Token.Kind != token.TokenEOF {
+		p.errors = append(p.errors, p.errorfAtToken(&p.Token, "expected token: <eof>, but: %s", p.Token.Kind))
+	}
+
+	return t, nil
+}
+
 // ParseDDL parses a CREATE/ALTER/DROP statement.
 func (p *Parser) ParseDDL() (ast.DDL, error) {
 	p.nextToken()