moss/src/tests/lexer.test.ts

import * as test from 'tape';

import Lexer, { LexerError, LexerResult } from '../lexer';
import Token, { TokenTypes as TT } from '../token';

const scan = (source: string): LexerResult => {
  return new Lexer(source).scan();
};

const EOF = (line: number = 1) => new Token(TT.EOF, 'eof', line);

test('scans punctuation', (t) => {
  t.plan(2);
  const result: LexerResult = scan('(),');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens.map((t) => t.type), [
      TT.LPAREN,
      TT.RPAREN,
      TT.COMMA,
      TT.EOF,
    ]);
  }
});

test('scans property', (t) => {
  t.plan(2);
  const result: LexerResult = scan(':property');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [new Token(TT.PROPERTY, 'property', 1), EOF()]);
  }
});

test('scans identifier', (t) => {
  t.plan(2);
  const result: LexerResult = scan('$identifier');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.IDENTIFIER, 'identifier', 1),
      EOF(),
    ]);
  }
});

test('scans function name', (t) => {
  t.plan(2);
  const result: LexerResult = scan('@function_name');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.FUNCTION_NAME, 'function_name', 1),
      EOF(),
    ]);
  }
});

test('scans literal', (t) => {
  t.plan(2);
  const result: LexerResult = scan('literal');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [new Token(TT.LITERAL, 'literal', 1), EOF()]);
  }
});

test('scans literal followed by parens', (t) => {
  t.plan(2);
  const result: LexerResult = scan('literal(literal)literal (');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LITERAL, 'literal', 1),
      new Token(TT.LPAREN, '(', 1),
      new Token(TT.LITERAL, 'literal', 1),
      new Token(TT.RPAREN, ')', 1),
      new Token(TT.LITERAL, 'literal', 1),
      new Token(TT.LPAREN, '(', 1),
      EOF(),
    ]);
  }
});

test('scans literal followed by property', (t) => {
  t.plan(2);
  const result: LexerResult = scan('literal :property');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LITERAL, 'literal', 1),
      new Token(TT.PROPERTY, 'property', 1),
      EOF(),
    ]);
  }
});

test('scans simple expression', (t) => {
  t.plan(2);
  const result: LexerResult = scan('(div :color blue)');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LPAREN, '(', 1),
      new Token(TT.LITERAL, 'div', 1),
      new Token(TT.PROPERTY, 'color', 1),
      new Token(TT.LITERAL, 'blue', 1),
      new Token(TT.RPAREN, ')', 1),
      EOF(),
    ]);
  }
});

test('keeps track of line numbers', (t) => {
  t.plan(2);
  const result: LexerResult = scan('line1\nline2');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LITERAL, 'line1', 1),
      new Token(TT.LITERAL, 'line2', 2),
      EOF(2),
    ]);
  }
});

test('scans literal followed by identifier', (t) => {
  t.plan(2);
  const result: LexerResult = scan('literal $identifier');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LITERAL, 'literal', 1),
      new Token(TT.IDENTIFIER, 'identifier', 1),
      EOF(),
    ]);
  }
});

test('allow dashes', (t) => {
  t.plan(2);
  const result: LexerResult = scan(
    'literal-dash $identifier-dash @function-dash'
  );
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LITERAL, 'literal-dash', 1),
      new Token(TT.IDENTIFIER, 'identifier-dash', 1),
      new Token(TT.FUNCTION_NAME, 'function-dash', 1),
      EOF(),
    ]);
  }
});

test('disallow whitespace in function arguments', (t) => {
  t.plan(2);
  const result: LexerResult = scan('(@rgba 0 0 0 0)');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LPAREN, '(', 1),
      new Token(TT.FUNCTION_NAME, 'rgba', 1),
      new Token(TT.LITERAL, '0', 1),
      new Token(TT.LITERAL, '0', 1),
      new Token(TT.LITERAL, '0', 1),
      new Token(TT.LITERAL, '0', 1),
      new Token(TT.RPAREN, ')', 1),
      EOF(),
    ]);
  }
});

test('ignores comments', (t) => {
  t.plan(2);
  const result: LexerResult = scan('; div with blue text\n(div :color blue)');
  t.false(result instanceof LexerError);
  if (!(result instanceof LexerError)) {
    t.deepEqual(result.tokens, [
      new Token(TT.LPAREN, '(', 2),
      new Token(TT.LITERAL, 'div', 2),
      new Token(TT.PROPERTY, 'color', 2),
      new Token(TT.LITERAL, 'blue', 2),
      new Token(TT.RPAREN, ')', 2),
      EOF(2),
    ]);
  }
});