require_relative "../test_helper" require "lox/ast_printer" require "lox/parser" require "lox/scanner" require "lox/token" class TestParser < Lox::Test def setup @ast_printer = Lox::AstPrinter.new @scanner = Lox::Scanner.new end def test_expression assert_parsed "(== 4.0 (>= 2.0 1.0))", :expression, "4 == 2 >= 1" end def test_term assert_parsed "(+ 4.0 (/ 2.0 1.0))", :term, "4 + 2 / 1" end def test_factor assert_parsed "(/ 4.0 (- 2.0))", :factor, "4 / -2" assert_parsed "(* 4.0 2.0)", :factor, "4 * 2" assert_parsed "(- 2.0)", :factor, "-2" end def test_unary assert_parsed "(! 42.0)", :unary, "!42" assert_parsed "(- 42.0)", :unary, "-42" assert_parsed "42.0", :unary, "42" end def test_primary assert_parsed "false", :primary, "false" assert_parsed "true", :primary, "true" assert_parsed "nil", :primary, "nil" assert_parsed "42.0", :primary, "42" assert_parsed "foo", :primary, "\"foo\"" assert_parsed "(group foo)", :primary, "(\"foo\")" end def test_errors e = assert_raises Lox::ParseError do parse("(42", :primary) end assert_equal "[line 1] Error at end: Expect ')' after expression.", e.message end def test_print assert_parsed "(print 42.0)", :statement, "print 42.0;" end def test_var assert_parsed "(var foo)", :declaration, "var foo;" assert_parsed "(var foo 42.0)", :declaration, "var foo = 42.0;" end def test_assign assert_parsed "(print (assign foo 42.0))", :declaration, "print foo = 42.0;" end def test_block assert_parsed "(block (var foo bar) (print (var foo)))", :statement, <<~SRC { var foo = "bar"; print foo; } SRC end def test_if assert_parsed "(if (var first) (if (var second) true false))", :statement, <<~SRC if (first) if (second) true; else false; SRC end def test_call assert_parsed "((var foo))", :statement, "foo();" assert_parsed "((var foo) (var bar))", :statement, "foo(bar);" assert_parsed "((var foo) (var bar) (var baz))", :statement, "foo(bar, baz);" end def test_return assert_parsed "(return)", :statement, "return;" assert_parsed "(return (var foo))", :statement, "return foo;" end def test_for assert_parsed <<~AST.chomp, :statement, "for(var i=0; i<3; i=i+1) print i;" (block (var i 0.0) (while (< (var i) 3.0) (block (print (var i)) (assign i (+ (var i) 1.0))))) AST end private def assert_parsed(expected, name, src) expr = parse(src, name) assert_equal expected, @ast_printer.print(expr) end def parse(src, name) tokens = @scanner.scan(src) Lox::Parser.new(tokens).send(name) end end