// MAP_TYPE -> map langle MAP_KEY_TYPE comma TYPE rangle [qstn]
// MAP_KEY_TYPE -> SIMPLE_TYPE | string | ENUM_TYPE
func (p *Parser) tryParseMapType() mojom.TypeRef {
if !p.OK() {
return nil
}
nextToken := p.peekNextToken("Trying to read a type.")
if nextToken.Kind != lexer.Name || nextToken.Text != "map" {
return nil
}
p.consumeNextToken()
if !p.match(lexer.LAngle) {
return nil
}
keyToken := p.peekNextToken("Trying to read a type.")
keyType := p.parseType()
p.match(lexer.Comma)
valueType := p.parseType()
if !p.match(lexer.RAngle) {
return nil
}
nullable := p.tryMatch(lexer.Qstn)
if !keyType.MarkUsedAsMapKey() {
message := fmt.Sprintf("The type %s at %s is not allowed as the key "+
"type of a map. Only simple types, strings and enum types may "+
"be map keys.",
keyType, keyToken.LongLocationString())
p.err = &ParseError{ParserErrorCodeUnexpectedToken, message}
return nil
}
return mojom.NewMapTypeRef(keyType, valueType, nullable)
}
// MAP_TYPE -> map langle MAP_KEY_TYPE comma TYPE rangle [qstn]
// MAP_KEY_TYPE -> SIMPLE_TYPE | string | ENUM_TYPE
func (p *Parser) tryReadMapType() mojom.TypeRef {
if !p.OK() {
return nil
}
nextToken := p.peekNextToken("Trying to read a type.")
if nextToken.Kind != lexer.NAME || nextToken.Text != "map" {
return nil
}
p.consumeNextToken()
if !p.match(lexer.LANGLE) {
return nil
}
keyToken := p.peekNextToken("Trying to read a type.")
keyType := p.parseType()
p.match(lexer.COMMA)
valueType := p.parseType()
if !p.match(lexer.RANGLE) {
return nil
}
nullable := p.tryMatch(lexer.QSTN)
if !keyType.MarkUsedAsMapKey() {
message := fmt.Sprintf("The type %s at %s is not allowed as the key "+
"type of a map. Only simple types, strings and enum types may "+
"be map keys.",
keyType, keyToken.LongLocationString())
p.err = &ParseError{E_UNEXPECTED_TOKEN, message}
return nil
}
return mojom.NewMapTypeRef(keyType, valueType, nullable)
}