hilbert.js/test/parsing-test.ts at d2e1d54ffbc1145056d7c7a30a763160b228d81b · mathigon/hilbert.js · GitHub

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// =============================================================================
// Hilbert.js | Parsing Tests
// (c) Mathigon
// =============================================================================


import tape from 'tape';
import {Expression} from '../src';


const expr = (src: string) => Expression.parse(src);
const str = (src: string) => expr(src).toString();


tape('basics', (test) => {
  test.equal(str('1'), '1');
  test.equal(str('-1'), '− 1');
  test.equal(str('x + y'), 'x + y');
  test.equal(str('aa + bb + cc'), 'aa + bb + cc');
  test.equal(str('5x + 2'), '5 x + 2');
  test.end();
});

tape('special operators', (test) => {
  test.equal(str('x - y'), 'x − y');
  test.equal(str('x – y'), 'x − y');
  test.equal(str('x − y'), 'x − y');
  test.end();
});

tape('functions', (test) => {
  test.equal(str('A_B'), 'A_B');
  test.equal(str('fn(A, B)'), 'fn(A, B)');
  test.end();
});

tape('commas', (test) => {
  test.equal(str('1,1'), '11');
  test.equal(str('1,1 + 2,2'), '11 + 22');
  test.equal(str('1,000 + 2,000'), '1000 + 2000');
  test.equal(str('1,'), '1'); // Trailing comma
  // test.equal(str(',1'), '1'); // Leading comma TODO: failing
  test.equal(str('1,2,3'), '123'); // Multiple commas
  test.equal(str('1,234,567.89'), '1234567.89'); // Multiple commas with a decimal point
  test.equal(str('1,,2'), '12'); // Multiple consecutive commas
  test.equal(str('1,2,'), '12'); // Multiple commas with trailing
  test.end();
});

tape('strings', (test) => {
  test.equal(str('"A" + "B"'), '"A" + "B"');
  test.equal(str('"A"_"B"'), '"A"_"B"');
  test.equal(str('fn(A_"B",C)'), 'fn(A_"B", C)');
  test.end();
});

tape('super and subscripts', (test) => {
  test.equal(str('x^(2_n)'), 'x^(2_n)');
  test.equal(str('(x^2)_n'), '(x^2)_n');
  test.equal(str('x_1^2 + 2^3_(n^2)'), 'x_1^2 + 2_(n^2)^3');
  test.equal(str('x_(n+1) = x_n / 2'), 'x_(n + 1) = x_n / 2');
  test.equal(str('x_n^2'), 'x_n^2');
  test.equal(str('x^2_n'), 'x_n^2');
  test.end();
});

tape('Comparison Operators', (test) => {
  test.equal(expr('a = b').collapse().toString(), 'a = b');
  test.equal(expr('a = b < c').collapse().toString(), 'a = b < c');
  test.equal(expr('a + 1 ≥ b + 2').collapse().toString(), 'a + 1 ≥ b + 2');
  test.end();
});

tape('Unary Minus', (test) => {
  test.throws(() => expr('1 * -1').collapse());
  test.throws(() => expr('1 + -1').collapse());
  test.doesNotThrow(() => expr('x = -1').collapse());
  test.end();
});

tape('symbols', (test) => {
  test.equal(str('oo'), '∞');
  test.equal(str('AA A'), '∀ A');
  test.equal(str('EE E'), '∃ E');
  test.equal(str('x in y'), 'x ∈ y');
  test.equal(str('x cup y'), 'x ∪ y');
  test.equal(str('x ∩ y'), 'x ∩ y');
  test.equal(str('a != b'), 'a ≠ b');
  test.equal(str('a ?= b'), 'a ≟ b');
  test.end();
});

tape('brackets', (test) => {
  test.equal(str('2 * (a + b)'), '2 · (a + b)');
  test.equal(str('2 * [a + b]'), '2 · [a + b]');
  test.equal(str('2 * {a + b}'), '2 · {a + b}');

  test.equal(str('2 * abs(a + b)'), '2 · abs(a + b)');
  test.equal(str('P(A | B)'), 'P(A | B)');

  test.throws(() => expr('(a + b]'));
  test.throws(() => expr('{a + b)'));
  test.throws(() => expr('[a + b}'));

  test.end();
});

tape('errors', (test) => {
  test.throws(() => expr('a + + b').collapse());
  test.throws(() => expr('a * - b').collapse());
  test.throws(() => expr('a + (a +)').collapse());
  test.throws(() => expr('a + (*)').collapse());
  test.throws(() => expr('(+) - a').collapse());
  test.throws(() => expr('2 =').collapse());
  test.throws(() => expr('2 = 1 =').collapse());
  test.throws(() => expr('< 1').collapse());
  test.end();
});

tape('extract functions, variables and unknowns', (test) => {
  const terms = expr('x * f(a+b)').collapse();
  test.same(terms.functions, ['×', 'f', '+']);
  test.same(terms.variables, ['x', 'a', 'b']);
  test.same(expr('y = e pi x').variables, ['y', 'e', 'π', 'x']);
  test.same(expr('y = e pi x').unknowns, ['y', 'x']);
  test.end();
});

tape('context', (test) => {
  const solution = expr('2x*(a+b)').collapse();
  const context = {variables: solution.variables};
  const student = Expression.parse('2x(a+b)', false, context).collapse();
  test.equals(student.toString(), solution.toString());
  test.end();
});

tape('mixed numbers', (test) => {
  test.equals(expr('1 1/2').collapse().toString(), '1 + 1 / 2');
  test.equals(expr('1 1/x').collapse().toString(), '1 + 1 / x');
  test.equals(expr('1 * 1/x').collapse().toString(), '1 × 1 / x');
  test.throws(() => expr('x 1/2').collapse());
  test.throws(() => expr('1/2 1/2').collapse());
  test.end();
});