Adding Support for arrays. TESTs do not pass, need to fix.
git-svn-id: https://svn.tlawal.org/svn/monkey@60 f6afcba9-9ef1-4bdd-9b72-7484f5705bac
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parent
40de215f70
commit
ef88c389f0
45
ast/ast.go
45
ast/ast.go
@ -296,3 +296,48 @@ type StringLiteral struct {
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func (sl *StringLiteral) expression_node() {}
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func (sl *StringLiteral) TokenLiteral() string { return sl.Token.Literal }
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func (sl *StringLiteral) String() string { return sl.Token.Literal }
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// Array Literal
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type ArrayLiteral struct {
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Token token.Token // the '[' token
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Elements []Expression
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}
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func (al *ArrayLiteral) expression_node() {}
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func (al *ArrayLiteral) TokenLiteral() string { return al.Token.Literal }
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func (al *ArrayLiteral) String() string {
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var out bytes.Buffer
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elements := []string{}
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for _, el := range al.Elements {
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elements = append(elements, el.String())
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}
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out.WriteString("[")
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out.WriteString(strings.Join(elements, ", "))
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out.WriteString("]")
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return out.String()
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}
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// Array Index Operator Expression
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type IndexExpression struct {
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Token token.Token // The [ token
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Left Expression
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Index Expression
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}
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func (ie *IndexExpression) expression_node() {}
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func (ie *IndexExpression) TokenLiteral() string { return ie.Token.Literal }
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func (ie *IndexExpression) String() string {
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var out bytes.Buffer
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out.WriteString("(")
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out.WriteString(ie.Left.String())
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out.WriteString("[")
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out.WriteString(ie.Index.String())
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out.WriteString("]")
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return out.String()
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}
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// Stopped at page 169
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@ -65,6 +65,10 @@ func (l_lexer *Lexer) NextToken() token.Token {
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case '"':
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tok.Type = token.STRING
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tok.Literal = l_lexer.read_string()
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case '[':
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tok = new_token(token.LBRACKET, l_lexer.current_char)
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case ']':
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tok = new_token(token.RBRACKET, l_lexer.current_char)
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case 0:
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tok.Literal = ""
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tok.Type = token.EOF
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@ -27,6 +27,7 @@ func TestNextToken(t *testing.T) {
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10 != 9;
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"foobar"
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"foo babr"
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[1,2];
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`
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tests := []struct {
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expectedType token.TokenType
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@ -116,6 +117,13 @@ func TestNextToken(t *testing.T) {
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{token.STRING, "foobar"},
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{token.STRING, "foo babr"},
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{token.LBRACKET, "["},
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{token.INT, "1"},
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{token.COMMA, ","},
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{token.INT, "2"},
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{token.RBRACKET, "]"},
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{token.SEMICOLON, ";"},
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{token.EOF, ""},
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}
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@ -18,6 +18,7 @@ const (
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PRODUCT // *
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PREFIX // -x OR !x
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CALL // simple_function(x)
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INDEX // array[index[
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)
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// Precedence Table
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@ -31,6 +32,7 @@ var precedences = map[token.TokenType]int{
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token.SLASH: PRODUCT,
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token.ASTERISK: PRODUCT,
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token.LPAREN: CALL,
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token.LBRACKET: INDEX,
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}
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func (l_parser *Parser) peek_precedence() int {
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@ -116,6 +118,10 @@ func New(l_lexer *lexer.Lexer) *Parser {
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// String
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l_parser.register_prefix(token.STRING, l_parser.parse_string_literal)
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// Array
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l_parser.register_prefix(token.LBRACKET, l_parser.parse_array_literal)
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l_parser.register_infix(token.LBRACKET, l_parser.parse_index_expression)
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return l_parser
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}
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@ -407,7 +413,7 @@ func (l_parser *Parser) parse_function_parameters() []*ast.Identifier {
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func (l_parser *Parser) parse_call_expression(function ast.Expression) ast.Expression {
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// defer untrace(trace("parse_call_expression"))
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expression := &ast.CallExpression{Token: l_parser.current_token, Function: function}
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expression.Arguments = l_parser.parse_call_arguments()
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expression.Arguments = l_parser.parse_expression_list(token.RPAREN)
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return expression
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}
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@ -441,3 +447,46 @@ func (l_parser *Parser) parse_string_literal() ast.Expression {
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Value: l_parser.current_token.Literal,
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}
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}
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// Array
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func (l_parser *Parser) parse_array_literal() ast.Expression {
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array := &ast.ArrayLiteral{Token: l_parser.current_token}
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array.Elements = l_parser.parse_expression_list(token.RBRACKET)
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return array
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}
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func (l_parser *Parser) parse_expression_list(end token.TokenType) []ast.Expression {
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list := []ast.Expression{}
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if l_parser.peek_token_is(end) {
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l_parser.next_token()
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return list
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}
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l_parser.next_token()
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list = append(list, l_parser.parse_expression(LOWEST))
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for l_parser.peek_token_is(token.COMMA) {
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l_parser.next_token()
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l_parser.next_token()
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list = append(list, l_parser.parse_expression(LOWEST))
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}
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if !l_parser.expect_peek(end) {
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return nil
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}
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return list
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}
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func (l_parser *Parser) parse_index_expression(left ast.Expression) ast.Expression {
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expression := &ast.IndexExpression{Token: l_parser.current_token, Left: left}
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l_parser.next_token()
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expression.Index = l_parser.parse_expression(LOWEST)
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if !l_parser.expect_peek(token.RBRACKET) {
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return nil
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}
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return expression
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}
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@ -322,6 +322,14 @@ func TestOperatorPrecedenceParsing(l_test *testing.T) {
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"add(a + b + c * d / f + g)",
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"add((((a + b) + ((c * d) / f)) + g))",
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},
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{
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"a * [1, 2, 3, 4][b * c] * d",
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"((a * ([1, 2, 3, 4][(b * c)])) * d)",
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},
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{
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"add(a * b[2], b[1], 2 * [1, 2][1])",
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"add((a * (b[2])), (b[1]), (2 * ([1, 2][1])))",
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},
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}
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for _, tt := range tests {
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l_lexer := lexer.New(tt.input)
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@ -676,6 +684,54 @@ func TestStringLiteralExpression(l_test *testing.T) {
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}
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}
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func TestParsingArrayLiterals(l_test *testing.T) {
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input := "[1, 2 * 2, 3 + 3]"
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l_lexer := lexer.New(input)
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l_parser := New(l_lexer)
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program := l_parser.ParseProgram()
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check_parser_errors(l_test, l_parser)
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statement, ok := program.Statements[0].(*ast.ExpressionStatement)
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array, ok := statement.Expression.(*ast.ArrayLiteral)
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if !ok {
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l_test.Fatalf("expression is not ast.ArrayLiteral, got=%T", statement.Expression)
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}
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if len(array.Elements) != 3 {
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l_test.Fatalf("len(array.Elements) not 3, got=%d", len(array.Elements))
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}
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testIntegerLiteral(l_test, array.Elements[0], 1)
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testInfixExpression(l_test, array.Elements[1], 2, "*", 2)
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testInfixExpression(l_test, array.Elements[2], 3, "+", 3)
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}
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func TestParsingIndexExpressions(l_test *testing.T) {
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input := "my_array[1+1]"
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l_lexer := lexer.New(input)
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l_parser := New(l_lexer)
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program := l_parser.ParseProgram()
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check_parser_errors(l_test, l_parser)
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statement, ok := program.Statements[0].(*ast.ExpressionStatement)
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index_expression, ok := statement.Expression.(*ast.IndexExpression)
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if !ok {
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l_test.Fatalf("expression is not *ast.IndexExpression, got=%T", statement.Expression)
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}
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if !testIdentifier(l_test, index_expression.Left, "my_array") {
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return
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}
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if !testInfixExpression(l_test, index_expression.Index, 1, "+", 1) {
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return
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}
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}
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// Helpers
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func check_parser_errors(l_test *testing.T, l_parser *Parser) {
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@ -38,6 +38,9 @@ const (
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LBRACE = "{"
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RBRACE = "}"
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LBRACKET = "["
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RBRACKET = "]"
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// Keywords
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FUNCTION = "FUNCTION"
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LET = "LET"
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