moss/src/tests/parser.test.ts

import * as test from 'tape';

import { AST } from '../ast';
import Lexer, { LexerError, LexerResult } from '../lexer';
import Parser, { ParserError, ParserResult } from '../parser';
import Token, { TokenTypes } from '../token';

const parse = (source: string) => {
  const lexerResult: LexerResult = new Lexer(source).scan();
  if (!(lexerResult instanceof LexerError)) {
    const parserResult: ParserResult = new Parser(lexerResult).parse();
    return parserResult;
  }

  return lexerResult;
};

const literalToken = (value: string): Token => {
  return new Token(TokenTypes.LITERAL, value, 1);
};

const propertyToken = (value: string): Token => {
  return new Token(TokenTypes.PROPERTY, value, 1);
};

const identifierToken = (value: string): Token => {
  return new Token(TokenTypes.IDENTIFIER, value, 1);
};

const literalNode = (value: string): AST.Literal => {
  return new AST.Literal(literalToken(value));
};

const identifierNode = (value: string): AST.Identifier => {
  return new AST.Identifier(identifierToken(value));
};

const property = (value: string): AST.Property => {
  const token = new Token(TokenTypes.PROPERTY, value, 1);
  return new AST.Property(token);
};

const functionName = (value: string): AST.Literal => {
  const token = new Token(TokenTypes.FUNCTION_NAME, value, 1);
  return new AST.Literal(token);
};

test('parses a literal', (t) => {
  t.plan(2);
  const result = parse('#FF0000');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [literalNode('#FF0000')]);
  }
});

test('parses a identifier', (t) => {
  t.plan(2);
  const result = parse('$blue');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [identifierNode('blue')]);
  }
});

test('parses an expression', (t) => {
  t.plan(2);
  const result = parse('(.para :color black)');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.RuleSet(
        [new AST.Selector(literalToken('.para'))],
        [new AST.Rule(property('color'), literalNode('black'))]
      ),
    ]);
  }
});

test('parses an expression with multiple selectors', (t) => {
  t.plan(2);
  const result = parse('(.header, .footer :color black)');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.RuleSet(
        [
          new AST.Selector(literalToken('.header')),
          new AST.Selector(literalToken('.footer')),
        ],
        [new AST.Rule(property('color'), literalNode('black'))]
      ),
    ]);
  }
});

test('parses an expression with children', (t) => {
  t.plan(2);
  const result = parse(
    '(body :color black (div :color blue (span :color red)))'
  );
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.RuleSet(
        [new AST.Selector(literalToken('body'))],
        [new AST.Rule(property('color'), literalNode('black'))],
        [
          new AST.RuleSet(
            [
              new AST.Selector(literalToken('div'), [
                new AST.Selector(literalToken('body')),
              ]),
            ],
            [new AST.Rule(property('color'), literalNode('blue'))],
            [
              new AST.RuleSet(
                [
                  new AST.Selector(literalToken('span'), [
                    new AST.Selector(literalToken('div'), [
                      new AST.Selector(literalToken('body')),
                    ]),
                  ]),
                ],
                [new AST.Rule(property('color'), literalNode('red'))]
              ),
            ]
          ),
        ]
      ),
    ]);
  }
});

test('parses a `let` call', (t) => {
  t.plan(2);
  const result = parse('(@let $blue #0000FF $red #FF0000)');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.Let(
        [
          new AST.Binding(identifierNode('blue'), literalNode('#0000FF')),
          new AST.Binding(identifierNode('red'), literalNode('#FF0000')),
        ],
        []
      ),
    ]);
  }
});

test('parses a `let` call with body', (t) => {
  t.plan(2);
  const result = parse(
    '(@let $blue #0000FF $red #FF0000 (div :background $blue :color $red))'
  );
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.Let(
        [
          new AST.Binding(identifierNode('blue'), literalNode('#0000FF')),
          new AST.Binding(identifierNode('red'), literalNode('#FF0000')),
        ],
        [
          new AST.RuleSet(
            [new AST.Selector(literalToken('div'))],
            [
              new AST.Rule(property('background'), identifierNode('blue')),
              new AST.Rule(property('color'), identifierNode('red')),
            ]
          ),
        ]
      ),
    ]);
  }
});

test('parses multiple rulesets in a let block', (t) => {
  t.plan(2);
  const result = parse(
    '(@let $blue #0000FF $red #FF0000 (div :background $blue) (span :color $red))'
  );
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.Let(
        [
          new AST.Binding(identifierNode('blue'), literalNode('#0000FF')),
          new AST.Binding(identifierNode('red'), literalNode('#FF0000')),
        ],
        [
          new AST.RuleSet(
            [new AST.Selector(literalToken('div'))],
            [new AST.Rule(property('background'), identifierNode('blue'))]
          ),
          new AST.RuleSet(
            [new AST.Selector(literalToken('span'))],
            [new AST.Rule(property('color'), identifierNode('red'))]
          ),
        ]
      ),
    ]);
  }
});

test('parses media query', (t) => {
  t.plan(2);
  const result = parse('(@media :min-width 1000px (div :flex-direction row))');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.MediaQuery(
        new AST.MediaQueryPredicate(
          property('min-width'),
          literalNode('1000px')
        ),
        [
          new AST.RuleSet(
            [new AST.Selector(literalToken('div'))],
            [new AST.Rule(property('flex-direction'), literalNode('row'))]
          ),
        ]
      ),
    ]);
  }
});

test('parses keyframes', (t) => {
  t.plan(2);
  const result = parse('(@keyframes fade (0% :opacity 1) (100% :opacity 0))');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.Keyframes(literalNode('fade'), [
        new AST.RuleSet(
          [new AST.Selector(literalToken('0%'))],
          [new AST.Rule(property('opacity'), literalNode('1'))]
        ),
        new AST.RuleSet(
          [new AST.Selector(literalToken('100%'))],
          [new AST.Rule(property('opacity'), literalNode('0'))]
        ),
      ]),
    ]);
  }
});

test('parses function call', (t) => {
  t.plan(2);
  const result = parse('(@rgba 255 0 0 0)');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.Application(functionName('rgba'), [
        literalNode('255'),
        literalNode('0'),
        literalNode('0'),
        literalNode('0'),
      ]),
    ]);
  }
});

test('parses mixin', (t) => {
  t.plan(2);
  const result = parse('(@mixin centered ($width) :max-width $width :margin auto)');
  t.false(result instanceof ParserError);
  if (!(result instanceof LexerError) && !(result instanceof ParserError)) {
    t.deepEqual(result.tree, [
      new AST.Mixin(
        literalToken('centered'),
        [
          identifierNode('width'),
        ],
        [
          new AST.Rule(
            new AST.Property(propertyToken('max-width')),
            identifierNode('width'),
          ),
          new AST.Rule(
            new AST.Property(propertyToken('margin')),
            literalNode('auto')
          ),
        ]
      ),
    ]);
  }
});