Golang lexer.NewSpanFromTokens函数代码示例

func (v *parser) parseMatchStat() *MatchStatNode {
	defer un(trace(v, "matchstat"))

	if !v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, KEYWORD_MATCH) {
		return nil
	}
	startToken := v.consumeToken()

	value := v.parseExpr()
	if value == nil {
		v.err("Expected valid expresson as value in match statement")
	}

	v.expect(lexer.TOKEN_SEPARATOR, "{")

	var cases []*MatchCaseNode
	for {
		if v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "}") {
			break
		}

		var pattern ParseNode
		if v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, "_") {
			patTok := v.consumeToken()

			pattern = &DefaultPatternNode{}
			pattern.SetWhere(patTok.Where)
		} else {
			pattern = v.parseExpr()
		}

		if pattern == nil {
			v.err("Expected valid expression as pattern in match statement")
		}

		v.expect(lexer.TOKEN_OPERATOR, "=>")

		var body ParseNode
		if v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "{") {
			body = v.parseBlock()
		} else {
			body = v.parseStat()
		}
		if body == nil {
			v.err("Expected valid arm statement in match clause")
		}

		v.expect(lexer.TOKEN_SEPARATOR, ",")

		caseNode := &MatchCaseNode{Pattern: pattern, Body: body}
		caseNode.SetWhere(lexer.NewSpan(pattern.Where().Start(), body.Where().End()))
		cases = append(cases, caseNode)
	}

	endToken := v.expect(lexer.TOKEN_SEPARATOR, "}")

	res := &MatchStatNode{Value: value, Cases: cases}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseTypeParameter() *TypeParameterNode {
	name := v.expect(lexer.TOKEN_IDENTIFIER, "")

	var restrictions []*NameNode
	if v.tokenMatches(0, lexer.TOKEN_OPERATOR, ":") {
		v.consumeToken()
		for {
			restriction := v.parseName()
			if restriction == nil {
				v.err("Expected valid name in type restriction")
			}
			restrictions = append(restrictions, restriction)

			if !v.tokenMatches(0, lexer.TOKEN_OPERATOR, "&") {
				break
			}
			v.consumeToken()
		}
	}

	res := &TypeParameterNode{Name: NewLocatedString(name), Restrictions: restrictions}
	if idx := len(restrictions) - 1; idx >= 0 {
		res.SetWhere(lexer.NewSpan(name.Where.Start(), restrictions[idx].Where().End()))
	} else {
		res.SetWhere(lexer.NewSpanFromTokens(name, name))
	}
	return res
}

func (v *parser) parseSizeofExpr() *SizeofExprNode {
	defer un(trace(v, "sizeofexpr"))

	if !v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, KEYWORD_SIZEOF) {
		return nil
	}
	startToken := v.consumeToken()

	v.expect(lexer.TOKEN_SEPARATOR, "(")

	var typ ParseNode
	value := v.parseExpr()
	if value == nil {
		typ = v.parseType(true)
		if typ == nil {
			v.err("Expected valid expression or type in sizeof expression")
		}
	}

	endToken := v.expect(lexer.TOKEN_SEPARATOR, ")")

	res := &SizeofExprNode{Value: value, Type: typ}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseBlock() *BlockNode {
	defer un(trace(v, "block"))

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "{") {
		return nil
	}
	startToken := v.consumeToken()

	var nodes []ParseNode
	for {
		node, is_cond := v.parseNode()
		if node == nil {
			break
		}
		if !is_cond {
			v.expect(lexer.TOKEN_SEPARATOR, ";")
		}
		nodes = append(nodes, node)
	}

	endToken := v.expect(lexer.TOKEN_SEPARATOR, "}")

	res := &BlockNode{Nodes: nodes}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseEnumType() *EnumTypeNode {
	defer un(trace(v, "enumtype"))

	if !v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, KEYWORD_ENUM) {
		return nil
	}
	startToken := v.consumeToken()

	v.expect(lexer.TOKEN_SEPARATOR, "{")

	var members []*EnumEntryNode
	for {
		if v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "}") {
			break
		}

		member := v.parseEnumEntry()
		if member == nil {
			v.err("Expected valid enum entry in enum")
		}
		members = append(members, member)

		if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ",") {
			break
		}
		v.consumeToken()
	}

	endToken := v.expect(lexer.TOKEN_SEPARATOR, "}")

	res := &EnumTypeNode{Members: members}

	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseToplevelDirective() ParseNode {
	defer un(trace(v, "toplevel-directive"))

	if !v.tokensMatch(lexer.TOKEN_OPERATOR, "#", lexer.TOKEN_IDENTIFIER, "") {
		return nil
	}
	start := v.expect(lexer.TOKEN_OPERATOR, "#")

	directive := v.expect(lexer.TOKEN_IDENTIFIER, "")
	switch directive.Contents {
	case "link":
		library := v.expect(lexer.TOKEN_STRING, "")
		res := &LinkDirectiveNode{Library: NewLocatedString(library)}
		res.SetWhere(lexer.NewSpanFromTokens(start, library))
		return res

	case "use":
		module := v.parseName()
		if module == nil {
			v.errPosSpecific(directive.Where.End(), "Expected name after use directive")
		}

		v.deps = append(v.deps, module)

		res := &UseDirectiveNode{Module: module}
		res.SetWhere(lexer.NewSpan(start.Where.Start(), module.Where().End()))
		return res

	default:
		v.errTokenSpecific(directive, "No such directive `%s`", directive.Contents)
		return nil
	}
}

func (v *parser) parseMatchStat() *MatchStatNode {
	if !v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, KEYWORD_MATCH) {
		return nil
	}
	startToken := v.consumeToken()

	value := v.parseExpr()
	if value == nil {
		v.err("Expected valid expresson as value in match statement")
	}

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "{") {
		v.err("Expected starting `{` after value in match statement, got `%s`", v.peek(0).Contents)
	}
	v.consumeToken()

	var cases []*MatchCaseNode
	for {
		if v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "}") {
			break
		}

		var pattern ParseNode
		if v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, "_") {
			patTok := v.consumeToken()

			pattern = &DefaultPatternNode{}
			pattern.SetWhere(patTok.Where)
		} else {
			pattern = v.parseExpr()
		}

		if pattern == nil {
			v.err("Expected valid expression as pattern in match statement")
		}

		if !v.tokenMatches(0, lexer.TOKEN_OPERATOR, "->") {
			v.err("Expected `->` after match pattern, got `%s`", v.peek(0).Contents)
		}
		v.consumeToken()

		body := v.parseStat()
		if body == nil {
			v.err("Expected valid statement as body in match statement")
		}

		caseNode := &MatchCaseNode{Pattern: pattern, Body: body}
		caseNode.SetWhere(lexer.NewSpan(pattern.Where().Start(), body.Where().End()))
		cases = append(cases, caseNode)
	}

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "}") {
		v.err("Expected closing `}` after match statement, got `%s`", v.peek(0).Contents)
	}
	endToken := v.consumeToken()

	res := &MatchStatNode{Value: value, Cases: cases}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseTypeDecl() *TypeDeclNode {
	defer un(trace(v, "typdecl"))

	if !v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, "type") {
		return nil
	}

	startToken := v.consumeToken()

	name := v.expect(lexer.TOKEN_IDENTIFIER, "")
	if isReservedKeyword(name.Contents) {
		v.err("Cannot use reserved keyword `%s` as type name", name.Contents)
	}

	genericSigil := v.parseGenericSigil()

	typ := v.parseType(true)

	endToken := v.expect(lexer.TOKEN_SEPARATOR, ";")

	res := &TypeDeclNode{
		Name:         NewLocatedString(name),
		GenericSigil: genericSigil,
		Type:         typ,
	}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))

	return res
}

func (v *parser) parseGenericSigil() *GenericSigilNode {
	defer un(trace(v, "genericsigil"))

	if !v.tokenMatches(0, lexer.TOKEN_OPERATOR, "<") {
		return nil
	}
	startToken := v.consumeToken()

	var parameters []*TypeParameterNode
	for {
		parameter := v.parseTypeParameter()
		if parameter == nil {
			v.err("Expected valid type parameter in generic sigil")
		}
		parameters = append(parameters, parameter)

		if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ",") {
			break
		}
		v.consumeToken()
	}
	endToken := v.expect(lexer.TOKEN_OPERATOR, ">")

	res := &GenericSigilNode{Parameters: parameters}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseArrayLit() *ArrayLiteralNode {
	defer un(trace(v, "arraylit"))

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "[") {
		return nil
	}
	startToken := v.consumeToken()

	var values []ParseNode
	for {
		if v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "]") {
			break
		}

		value := v.parseExpr()
		if value == nil {
			v.err("Expected valid expression in array literal")
		}
		values = append(values, value)

		if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ",") {
			break
		}
		v.consumeToken()
	}

	endToken := v.expect(lexer.TOKEN_SEPARATOR, "]")

	res := &ArrayLiteralNode{Values: values}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseTupleLit() *TupleLiteralNode {
	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "(") {
		return nil
	}
	startToken := v.consumeToken()

	var values []ParseNode
	for {
		if v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ")") {
			break
		}

		value := v.parseExpr()
		if value == nil {
			v.err("Expected valid expression in tuple literal")
		}
		values = append(values, value)

		if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ",") {
			break
		}
		v.consumeToken()
	}

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ")") {
		v.err("Expected closing `]` after tuple literal, got `%s`", v.peek(0).Contents)
	}
	endToken := v.consumeToken()

	res := &TupleLiteralNode{Values: values}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseTupleType() *TupleTypeNode {
	defer un(trace(v, "tupletype"))

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "(") {
		return nil
	}
	startToken := v.consumeToken()

	var members []ParseNode
	for {
		memberType := v.parseType(true)
		if memberType == nil {
			v.err("Expected valid type in tuple type")
		}
		members = append(members, memberType)

		if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ",") {
			break
		}
		v.consumeToken()
	}

	endToken := v.expect(lexer.TOKEN_SEPARATOR, ")")

	res := &TupleTypeNode{MemberTypes: members}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseCastExpr() *CastExprNode {
	if !v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, KEYWORD_CAST) {
		return nil
	}
	startToken := v.consumeToken()

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "(") {
		v.err("Expected opening `(` in cast expression, got `%s`", v.peek(0).Contents)
	}
	v.consumeToken()

	typ := v.parseType()
	if typ == nil {
		v.err("Expected valid type in cast expression")
	}

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ",") {
		v.err("Expected `,` in cast expresion, got `%s`", v.peek(0).Contents)
	}
	v.consumeToken()

	value := v.parseExpr()
	if value == nil {
		v.err("Expected valid expression in cast expression")
	}

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ")") {
		v.err("Expected closing `)` after cast expression, got `%s`", v.peek(0).Contents)
	}
	endToken := v.consumeToken()

	res := &CastExprNode{Type: typ, Value: value}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseSizeofExpr() *SizeofExprNode {
	if !v.tokenMatches(0, lexer.TOKEN_IDENTIFIER, KEYWORD_SIZEOF) {
		return nil
	}
	startToken := v.consumeToken()

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, "(") {
		v.err("Expected opening `(` in sizeof expression, got `%s`", v.peek(0).Contents)
	}
	v.consumeToken()

	value := v.parseExpr()
	if value == nil {
		v.err("Expected valid expression in sizeof expression")
	}

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ")") {
		v.err("Expected closing `)` after sizeof expression, got `%s`", v.peek(0).Contents)
	}
	endToken := v.consumeToken()

	res := &SizeofExprNode{Value: value}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}

func (v *parser) parseTupleType() *TupleTypeNode {
	startToken := v.consumeToken()

	var members []ParseNode
	for {
		memberType := v.parseType()
		if memberType == nil {
			v.err("Expected valid type in tuple type")
		}
		members = append(members, memberType)

		if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ",") {
			break
		}
		v.consumeToken()
	}

	if !v.tokenMatches(0, lexer.TOKEN_SEPARATOR, ")") {
		v.err("Expected closing `)` after tuple type, got `%s`", v.peek(0).Contents)
	}
	endToken := v.consumeToken()

	res := &TupleTypeNode{MemberTypes: members}
	res.SetWhere(lexer.NewSpanFromTokens(startToken, endToken))
	return res
}