parse statements

parser/parser_test.go

@@ -0,0 +1,120 @@
+package parser
+
+import (
+	"testing"
+
+	"gointerpreter/ast"
+	"gointerpreter/lexer"
+)
+
+func Test_LetStatement(t *testing.T) {
+	input := `
+    let x = 5;
+    let y = 10;
+    let foobar = 324453;
+    `
+
+	l := lexer.New(input)
+	p := New(l)
+
+	program := p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if program == nil {
+		t.Fatalf("ParseProgram() returned nil")
+	}
+
+	if len(program.Statements) != 3 {
+		t.Fatalf("program.Statement does not contained 3 statements, got [%d]", len(program.Statements))
+	}
+
+	tests := []struct {
+		expectedIdentifier string
+	}{
+		{"x"},
+		{"y"},
+		{"foobar"},
+	}
+
+	for i, tt := range tests {
+		statement := program.Statements[i]
+
+		if !testLetStatement(t, statement, tt.expectedIdentifier) {
+			return
+		}
+	}
+}
+
+func testLetStatement(t *testing.T, s ast.Statement, name string) bool {
+	if s.TokenLiteral() != "let" {
+		t.Errorf("s.TokenLiteral() is not [let], got [%s]", s.TokenLiteral())
+		return false
+	}
+
+	letStatement, ok := s.(*ast.LetStatement)
+	if !ok {
+		t.Errorf("s is not a *ast.LetStatement, got [%T]", s)
+		return false
+	}
+
+	if letStatement.Name.Value != name {
+		t.Errorf("letStatement.Name.Value is not [%s], got [%s]", name, letStatement.Name.Value)
+		return false
+	}
+
+	if letStatement.Name.TokenLiteral() != name {
+		t.Errorf("letStatement.TokenLiteral() is not [%s], got [%s]", name, letStatement.TokenLiteral())
+		return false
+	}
+
+	return true
+}
+
+func checkParserErrors(t *testing.T, p *Parser) {
+	errors := p.Errors()
+
+	if len(errors) == 0 {
+		return
+	}
+
+	t.Errorf("parser has [%d] errors", len(errors))
+	for _, e := range errors {
+		t.Errorf("parser error: %q", e)
+	}
+
+	t.FailNow()
+}
+
+func Test_ReturnStatement(t *testing.T) {
+	input := `
+    return 5;
+    return 10;
+    return 234342;
+    `
+
+	l := lexer.New(input)
+	p := New(l)
+
+	program := p.ParseProgram()
+	checkParserErrors(t, p)
+
+	if program == nil {
+		t.Fatalf("ParseProgram() returned nil")
+	}
+
+	if len(program.Statements) != 3 {
+		t.Fatalf("program.Statement does not contained 3 statements, got [%d]", len(program.Statements))
+	}
+
+	for _, stmt := range program.Statements {
+		returnStmt, ok := stmt.(*ast.ReturnStatement)
+		if !ok {
+			t.Errorf("stmt is not *ast.ReturnStatement, got [%T]", stmt)
+			continue
+		}
+
+		if returnStmt.TokenLiteral() != "return" {
+			t.Errorf("returnStmt.TokenLiteral() is not [return], got [%q]", returnStmt.TokenLiteral())
+		}
+	}
+}