utils/tests/peg/peg_test.dart

// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

library peg_tests;
import '../../peg/pegparser.dart';

testParens() {
  Grammar g = new Grammar();
  Symbol a = g['A'];

  a.def = ['(', MANY(a, min:0), ')', (a) => a];

  check(g, a, "", null);
  check(g, a, "()", '[]');
  check(g, a, "(()())", '[[],[]]');
  check(g, a, "(()((()))())", '[[],[[[]]],[]]');
}

testBlockComment() {

  // Block comment in whitespace.

  Grammar g = new Grammar();
  Symbol blockComment = g['blockComment'];

  blockComment.def =
      ['/*',
       MANY(OR([blockComment,
                [NOT('*/'), CHAR()],
                [END, ERROR('EOF in block comment')]
                ]),
            min: 0),
       '*/'];
  print(blockComment);

  var a = MANY(TEXT('x'));

  g.whitespace = OR([g.whitespace, blockComment]);

  check(g, a, "x /**/ x", '[x,x]');
  check(g, a, "x /*/**/*/ x", '[x,x]');
  check(g, a, "x /*/***/ x", 'EOF in block comment');
  check(g, a, "x /*/*/x**/**/ x", '[x,x]');

  check(g, a, r"""
/* Comment */
/* Following comment with /* nested comment*/ */
x
/* x in comment */
x /* outside comment */
""",
        '[x,x]');
}

testTEXT() {
  Grammar g = new Grammar();

  // TEXT grabs the parsed text,
  check(g, TEXT(LEX(MANY(OR(['1','a'])))), '  1a1  ', '1a1');

  // Without the lexical context, TEXT will grab intervening whitespace.
  check(g, TEXT(MANY(OR(['1','a']))), '  1a1  ', '1a1');
  check(g, TEXT(MANY(OR(['1','a']))), '  1  a 1  ', '1  a 1');

  // Custom processing of the TEXT substring.
  var binaryNumber =
      TEXT(LEX(MANY(OR(['0','1']))),
           (str, start, end) {
             var r = 0;
             var zero = '0'.codeUnitAt(0);
             for (int i = start; i < end; i++)
               r = r * 2 + (str.codeUnitAt(i) - zero);
             return r;
           });

  check(g, binaryNumber, ' 10101 ', 21);
  check(g, binaryNumber, '1010111', 87);
  check(g, binaryNumber, '1010 111', null);
}

testOR() {
  // OR matches the first match.
  Grammar g = new Grammar();
  check(g, OR([['a', NOT(END), () => 1],
               ['a', () => 2],
               ['a', () => 3]]),
        'a', 2);
}

testCODE() {
  Grammar g = new Grammar();
  var a = TEXT(LEX('thing', MANY(CHAR('bcd'))));

  check(g, a, 'bbb', 'bbb');
  check(g, a, 'ccc', 'ccc');
  check(g, a, 'ddd', 'ddd');
  check(g, a, 'bad', null);  // a is outside range.
  check(g, a, 'bed', null);  // e is outside range.
}

testC() {
  // Curried tree builders.
  binary(operation) => (second) => (first) => [operation, first, second];
  unary(operation) => () => (first) => [operation, first];
  reform(a, fns) {
    var r = a;
    for (var fn in fns)
      r = fn(r);
    return r;
  }

  Grammar g = new Grammar();

  Symbol expression = g['expression'];
  Symbol postfix_e = g['postfix_e'];
  Symbol unary_e = g['unary_e'];
  Symbol cast_e = g['cast_e'];
  Symbol mult_e = g['mult_e'];
  Symbol add_e = g['add_e'];
  Symbol shift_e = g['shift_e'];
  Symbol relational_e = g['relational_e'];
  Symbol equality_e = g['equality_e'];
  Symbol cond_e = g['cond_e'];
  Symbol assignment_e = g['assignment_e'];

  // Lexical elements.
  var idStartChar = CHAR(
      r"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz");
  var idNextChar = CHAR(
      r"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789$_");

  var id = TEXT(LEX('identifier', [idStartChar, MANY(idNextChar, min: 0)]));

  var lit = TEXT(LEX('literal', MANY(CHAR('0123456789'))));


  var type_name = id;


  // Expression grammar.
  var primary_e = OR([id,
                      lit,
                      ['(', expression, ')', (e) => e]
                      ]);

  var postfixes = OR([['(', MANY(assignment_e, ',', 0), ')', binary('apply')],
                      ['++', unary('postinc')],
                      ['--', unary('postdec')],
                      ['.', id, binary('field')],
                      ['->', id, binary('ptr')],
                      ]);

  postfix_e.def = [primary_e, MANY(postfixes, min:0), reform];


  var unary_op = OR([['&', () => 'address'],
                     ['*', () => 'indir'],
                     ['!', () => 'not'],
                     ['~', () => 'not'],
                     ['-', () => 'negate'],
                     ['+', () => 'uplus'],
                     ]);
  var sizeof = LEX('sizeof', ['sizeof', NOT(idNextChar)]);

  Symbol unary_e_plain = g['unary_e_plain'];
  unary_e_plain.def =
      OR([ ['++', unary_e, (e) => ['preinc', e]],
           ['--', unary_e, (e) => ['predec', e]],
           [unary_op, cast_e, (o, e) => [o, e]],
           [sizeof, unary_e, (e) => ['sizeof-expr', e]],
           [sizeof, '(', type_name , ')', (t) => ['sizeof-type', t]],
           postfix_e
           ]);

  unary_e.def = MEMO(unary_e_plain);
  //unary_e.def = unary_e_plain;

  cast_e.def = OR([ ['(', type_name, ')', cast_e, (t, e) => ['cast', t, e]],
                    unary_e,
                         ]);

  var mult_ops = OR([['*', cast_e, binary('mult')],
                     ['/', cast_e, binary('div')],
                     ['%', cast_e, binary('rem')],
                     ]);
  mult_e.def = [cast_e, MANY(mult_ops, min:0), reform];

  var add_ops = OR([['+', mult_e, binary('add')],
                    ['-', mult_e, binary('sub')],
                    ]);
  add_e.def = [mult_e, MANY(add_ops, min:0), reform];

  var shift_ops = OR([['>>', add_e, binary('shl')],
                      ['<<', add_e, binary('shr')],
                      ]);
  shift_e.def = [add_e, MANY(shift_ops, min:0), reform];

  var relational_ops = OR([['<=', shift_e, binary('le')],
                           ['>=', shift_e, binary('ge')],
                           ['<', shift_e, binary('lt')],
                           ['>', shift_e, binary('gt')],
                           ]);
  relational_e.def = [shift_e, MANY(relational_ops, min:0), reform];


  var equality_ops = OR([['==', shift_e, binary('eq')],
                         ['!=', shift_e, binary('ne')],
                         ]);
  equality_e.def = [relational_e, MANY(equality_ops, min:0), reform];


  var bit_and_op = LEX('&', ['&', NOT('&')]);  // Don't see '&&' and '&', '&'
  var bit_or_op = LEX('|', ['|', NOT('|')]);

  var and_e = [equality_e, MANY([bit_and_op, equality_e, binary('bitand')], min:0), reform];
  var xor_e = [and_e, MANY(['^', and_e, binary('bitxor')], min:0), reform];
  var or_e = [xor_e, MANY([bit_or_op, xor_e, binary('bitor')], min:0), reform];

  var log_and_e = [or_e, MANY(['&&', or_e, binary('and')], min:0), reform];

  var log_or_e = [log_and_e, MANY(['||', log_and_e, binary('or')], min:0), reform];

  //cond_e.def = OR([ [log_or_e, '?', expression, ':', cond_e,
  //                   (p,a,b) => ['cond', p, a, b]],
  //                  log_or_e]);
  // Alternate version avoids reparsing log_or_e.
  cond_e.def = [log_or_e, MAYBE(['?', expression, ':', cond_e]),
                (p, r) => r == null || r == false ? p : ['cond', p, r[0], r[1]]];

  var assign_op = OR([['*=', () => 'mulassign'],
                      ['=', () => 'assign']]);

  // TODO: Figure out how not to re-parse a unary_e.
  // Order matters - cond_e can't go first since cond_e will succeed on, e.g. 'a'.
  assignment_e.def = OR([[unary_e, assign_op, assignment_e,
                          (u, op, a) => [op, u, a]],
                         cond_e]);

  expression.def = [assignment_e,
                    MANY([',', assignment_e, binary('comma')], min:0),
                    reform];

  show(g, expression, 'a');
  check(g, expression, 'a', 'a');
  check(g, expression, '(a)', 'a');
  check(g, expression, '  (  ( a ) ) ', 'a');

  check(g, expression, 'a(~1,2)',  '[apply,a,[[not,1],2]]');
  check(g, expression, 'a(1)(x,2)', '[apply,[apply,a,[1]],[x,2]]');
  check(g, expression, 'a(1,2())', '[apply,a,[1,[apply,2,[]]]]');

  check(g, expression, '++a++', '[preinc,[postinc,a]]');
  check(g, expression, 'a++++b', null);
  check(g, expression, 'a++ ++b', null);
  check(g, expression, 'a+ +++b', '[add,a,[preinc,[uplus,b]]]');
  check(g, expression, 'a+ + ++b', '[add,a,[uplus,[preinc,b]]]');
  check(g, expression, 'a+ + + +b', '[add,a,[uplus,[uplus,[uplus,b]]]]');
  check(g, expression, 'a+ ++ +b', '[add,a,[preinc,[uplus,b]]]');
  check(g, expression, 'a++ + +b', '[add,[postinc,a],[uplus,b]]');
  check(g, expression, 'a+++ +b', '[add,[postinc,a],[uplus,b]]');

  check(g, expression, '((T)f)(x)', '[apply,[cast,T,f],[x]]');
  check(g, expression, '(T)f(x)', '[cast,T,[apply,f,[x]]]');

  check(g, expression, 'a++*++b', '[mult,[postinc,a],[preinc,b]]');

  check(g, expression, 'a<<1>>++b', '[shl,[shr,a,1],[preinc,b]]');

  check(g, expression, 'a<1&&b', '[and,[lt,a,1],b]');

  check(g, expression, 'a<1 & &b', '[bitand,[lt,a,1],[address,b]]');
  check(g, expression,
        'a ? b ? c : d : e ? f : g',
        '[cond,a,[cond,b,c,d],[cond,e,f,g]]');

  check(g, expression, 'a,b,c', '[comma,[comma,a,b],c]');
  check(g, expression, 'a=1,b,c', '[comma,[comma,[assign,a,1],b],c]');

  check(g, expression,
        '((((((((((((a))))))))))))=1,b,c', '[comma,[comma,[assign,a,1],b],c]');

  check(g, expression, 'sizeof a', '[sizeof-expr,a]');
  check(g, expression, 'sizeofa', 'sizeofa');
  check(g, expression, 'sizeof (a)', '[sizeof-expr,a]');
}


show(grammar, rule, input) {
  print('show: "$input"');
  var ast;
  try {
    ast = grammar.parse(rule, input);
  } catch (exception) {
    if (exception is ParseError)
      ast = exception;
    else
      throw;
  }
  print('${printList(ast)}');
}

void check(grammar, rule, input, expected) {
  // If [expected] is String then the result is coerced to string.
  // If [expected] is !String, the result is compared directly.
  print('check: "$input"');
  var ast;
  try {
    ast = grammar.parse(rule, input);
  } catch (exception) {
    ast = exception;
  }

  var formatted = ast;
  if (expected is String)
    formatted = printList(ast);

  Expect.equals(expected, formatted, "parse: $input");
}

// Prints the list in [1,2,3] notation, including nested lists.
printList(item) {
  if (item is List) {
    StringBuffer sb = new StringBuffer();
    sb.write('[');
    var sep = '';
    for (var x in item) {
      sb.write(sep);
      sb.write(printList(x));
      sep = ',';
    }
    sb.write(']');
    return sb.toString();
  }
  if (item == null)
    return 'null';
  return item.toString();
}

main() {
  testCODE();
  testParens();
  testOR();
  testTEXT();
  testBlockComment();
  testC();
}