waiig15/parser/parser_let.go

package parser

import (
	"code.osinet.fr/fgm/waiig15/ast"
	"code.osinet.fr/fgm/waiig15/token"
)

func (p *Parser) parseLetStatement() *ast.LetStatement {
	defer untrace(trace("parseLetStatement"))
	stmt := &ast.LetStatement{
		Token: p.curToken,
	}

	// Let statement starts with an IDENT token, so if next token is not an
	// IDENT, the next statement cannot be a Let statement.
	if !p.expectPeek(token.IDENT) {
		return nil
	}

	stmt.Name = &ast.Identifier{
		Token: p.curToken,
		Value: p.curToken.Literal,
	}

	// The previous expectPeek() call fetched the next token, so we should now
	// be on the assignment.
	if !p.expectPeek(token.ASSIGN) {
		return nil
	}

	// Skip the expression for now, progress to the semicolon terminating the
	// statement.
	for !p.curTokenIs(token.SEMICOLON) {
		p.nextToken()
	}

	return stmt
}