parser:init pratt parser. parser:add prefix, infix and `parseIntegerLiteral`

1 files changed, 70 insertions, 0 deletions

diff --git a/parser/parser_test.go b/parser/parser_test.go
index 8e06ecd..cd1d506 100644
--- a/parser/parser_test.go
+++ b/parser/parser_test.go
@@ -122,3 +122,73 @@ func TestReturnStatements(t *testing.T) {
 		}
 	}
 }
+
+// Identifier expression tests.
+func TestIdentifierExpression(t *testing.T) {
+	var input string = "foobar;"
+
+	var l *lexer.Lexer = lexer.New(input)
+	var p *Parser = New(l)
+	var program *ast.Program = p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if len(program.Statements) != 1 {
+		t.Fatalf("program has not enough statements. got=%d", len(program.Statements))
+	}
+
+	stmt, ok := program.Statements[0].(*ast.ExpressionStatement)
+
+	if !ok {
+		t.Fatalf("program.Statements[0] is not ast.ExpressionStatement. got=%T", program.Statements[0])
+	}
+
+	ident, ok := stmt.Expression.(*ast.Identifier)
+
+	if !ok {
+		t.Fatalf("exp not *ast.Identifier. got=%T", stmt.Expression)
+	}
+
+	if ident.Value != "foobar" {
+		t.Errorf("ident.Value not %s. got=%s", "foobar", ident.Value)
+	}
+
+	if ident.TokenLiteral() != "foobar" {
+		t.Errorf("ident.TokenLiteral not %s. got=%s", "foobar", ident.TokenLiteral())
+	}
+}
+
+// Integer literal expression tests.
+func TestIntegerLiteralExpression(t *testing.T) {
+	var input string = "5;"
+
+	var l *lexer.Lexer = lexer.New(input)
+	var p *Parser = New(l)
+	var program *ast.Program = p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if len(program.Statements) != 1 {
+		t.Fatalf("program has not enough statements. got=%d", len(program.Statements))
+	}
+
+	stmt, ok := program.Statements[0].(*ast.ExpressionStatement)
+
+	if !ok {
+		t.Fatalf("program.Statements[0] is not ast.ExpressionStatement. got=%T", program.Statements[0])
+	}
+
+	literal, ok := stmt.Expression.(*ast.IntegerLiteral)
+
+	if !ok {
+		t.Fatalf("exp not *ast.IntegerLiteral. got=%T", stmt.Expression)
+	}
+
+
+	if literal.Value != 5 {
+		t.Errorf("literal.Value not %d. got=%d", 5, literal.Value)
+	}
+
+	if literal.TokenLiteral() != "5" {
+		t.Errorf("literal.TokenLiteral not %s. got=%s", "5", literal.TokenLiteral())
+	}
+}
+