hy/tests/test_lex.py

# Copyright 2019 the authors.
# This file is part of Hy, which is free software licensed under the Expat
# license. See the LICENSE.
import sys
import traceback

import pytest

from math import isnan
from hy.models import (HyExpression, HyInteger, HyFloat, HyComplex, HySymbol,
                       HyString, HyDict, HyList, HySet, HyKeyword)
from hy.lex import tokenize
from hy.lex.exceptions import LexException, PrematureEndOfInput
from hy.errors import hy_exc_handler

def peoi(): return pytest.raises(PrematureEndOfInput)
def lexe(): return pytest.raises(LexException)


def check_ex(execinfo, expected):
    output = traceback.format_exception_only(execinfo.type, execinfo.value)
    assert output[:-1] == expected[:-1]
    # Python 2.7 doesn't give the full exception name, so we compensate.
    assert output[-1].endswith(expected[-1])


def check_trace_output(capsys, execinfo, expected):
   sys.__excepthook__(execinfo.type, execinfo.value, execinfo.tb)
   captured_wo_filtering = capsys.readouterr()[-1].strip('\n')

   hy_exc_handler(execinfo.type, execinfo.value, execinfo.tb)
   captured_w_filtering = capsys.readouterr()[-1].strip('\n')

   output = captured_w_filtering.split('\n')

   # Make sure the filtered frames aren't the same as the unfiltered ones.
   assert output[:-1] != captured_wo_filtering.split('\n')[:-1]
   # Remove the origin frame lines.
   assert output[3:-1] == expected[:-1]
   # Python 2.7 doesn't give the full exception name, so we compensate.
   assert output[-1].endswith(expected[-1])


def test_lex_exception():
    """ Ensure tokenize throws a fit on a partial input """
    with peoi(): tokenize("(foo")
    with peoi(): tokenize("{foo bar")
    with peoi(): tokenize("(defn foo [bar]")
    with peoi(): tokenize("(foo \"bar")


def test_unbalanced_exception():
    """Ensure the tokenization fails on unbalanced expressions"""
    with lexe(): tokenize("(bar))")
    with lexe(): tokenize("(baz [quux]])")


def test_lex_single_quote_err():
    "Ensure tokenizing \"' \" throws a LexException that can be stringified"
    # https://github.com/hylang/hy/issues/1252
    with lexe() as execinfo:
        tokenize("' ")
    check_ex(execinfo, [
        '  File "<string>", line -1\n',
        "    '\n",
        '    ^\n',
        'LexException: Could not identify the next token.\n'])


def test_lex_expression_symbols():
    """ Make sure that expressions produce symbols """
    objs = tokenize("(foo bar)")
    assert objs == [HyExpression([HySymbol("foo"), HySymbol("bar")])]


def test_lex_expression_strings():
    """ Test that expressions can produce strings """
    objs = tokenize("(foo \"bar\")")
    assert objs == [HyExpression([HySymbol("foo"), HyString("bar")])]


def test_lex_expression_integer():
    """ Make sure expressions can produce integers """
    objs = tokenize("(foo 2)")
    assert objs == [HyExpression([HySymbol("foo"), HyInteger(2)])]


def test_lex_symbols():
    """ Make sure that symbols are valid expressions"""
    objs = tokenize("foo ")
    assert objs == [HySymbol("foo")]


def test_lex_strings():
    """ Make sure that strings are valid expressions"""
    objs = tokenize('"foo"')
    assert objs == [HyString("foo")]
    # Make sure backslash-escaped newlines work (see issue #831)
    objs = tokenize(r"""
"a\
bc"
""")
    assert objs == [HyString("abc")]


def test_lex_strings_exception():
    """ Make sure tokenize throws when codec can't decode some bytes"""
    with lexe() as execinfo:
        tokenize('\"\\x8\"')
    check_ex(execinfo, [
        '  File "<string>", line 1\n',
        '    "\\x8"\n',
        '    ^\n',
        'LexException: Can\'t convert "\\x8" to a HyString\n'])


def test_lex_bracket_strings():

    objs = tokenize("#[my delim[hello world]my delim]")
    assert objs == [HyString("hello world")]
    assert objs[0].brackets == "my delim"

    objs = tokenize("#[[squid]]")
    assert objs == [HyString("squid")]
    assert objs[0].brackets == ""


def test_lex_integers():
    """ Make sure that integers are valid expressions"""
    objs = tokenize("42 ")
    assert objs == [HyInteger(42)]


def test_lex_fractions():
    """ Make sure that fractions are valid expressions"""
    objs = tokenize("1/2")
    assert objs == [HyExpression([HySymbol("fraction"), HyInteger(1),
                                  HyInteger(2)])]


def test_lex_expression_float():
    """ Make sure expressions can produce floats """
    objs = tokenize("(foo 2.)")
    assert objs == [HyExpression([HySymbol("foo"), HyFloat(2.)])]
    objs = tokenize("(foo -0.5)")
    assert objs == [HyExpression([HySymbol("foo"), HyFloat(-0.5)])]
    objs = tokenize("(foo 1.e7)")
    assert objs == [HyExpression([HySymbol("foo"), HyFloat(1.e7)])]


def test_lex_big_float():
    # https://github.com/hylang/hy/issues/1448
    assert tokenize("1e900") == [HyFloat(1e900)]
    assert tokenize("1e900-1e900j") == [HyComplex(1e900, -1e900)]


def test_lex_nan_and_inf():

    assert isnan(tokenize("NaN")[0])
    assert tokenize("Nan") == [HySymbol("Nan")]
    assert tokenize("nan") == [HySymbol("nan")]
    assert tokenize("NAN") == [HySymbol("NAN")]

    assert tokenize("Inf") == [HyFloat(float("inf"))]
    assert tokenize("inf") == [HySymbol("inf")]
    assert tokenize("INF") == [HySymbol("INF")]

    assert tokenize("-Inf") == [HyFloat(float("-inf"))]
    assert tokenize("-inf") == [HySymbol("-inf")]
    assert tokenize("-INF") == [HySymbol("-INF")]


def test_lex_expression_complex():
    """ Make sure expressions can produce complex """

    def t(x): return tokenize("(foo {})".format(x))

    def f(x): return [HyExpression([HySymbol("foo"), x])]

    assert t("2.j") == f(HyComplex(2.j))
    assert t("-0.5j") == f(HyComplex(-0.5j))
    assert t("1.e7j") == f(HyComplex(1e7j))
    assert t("j") == f(HySymbol("j"))
    assert isnan(t("NaNj")[0][1].imag)
    assert t("nanj") == f(HySymbol("nanj"))
    assert t("Inf+Infj") == f(HyComplex(complex(float("inf"), float("inf"))))
    assert t("Inf-Infj") == f(HyComplex(complex(float("inf"), float("-inf"))))
    assert t("Inf-INFj") == f(HySymbol("Inf-INFj"))


def test_lex_digit_separators():

    assert tokenize("1_000_000") == [HyInteger(1000000)]
    assert tokenize("1,000,000") == [HyInteger(1000000)]
    assert tokenize("1,000_000") == [HyInteger(1000000)]
    assert tokenize("1_000,000") == [HyInteger(1000000)]

    assert tokenize("0x_af") == [HyInteger(0xaf)]
    assert tokenize("0x,af") == [HyInteger(0xaf)]
    assert tokenize("0b_010") == [HyInteger(0b010)]
    assert tokenize("0b,010") == [HyInteger(0b010)]
    assert tokenize("0o_373") == [HyInteger(0o373)]
    assert tokenize("0o,373") == [HyInteger(0o373)]

    assert tokenize('1_2.3,4') == [HyFloat(12.34)]
    assert tokenize('1_2e3,4') == [HyFloat(12e34)]
    assert (tokenize("1,2/3_4") ==
            [HyExpression([HySymbol("fraction"),
             HyInteger(12), HyInteger(34)])])
    assert tokenize("1,0_00j") == [HyComplex(1000j)]

    assert tokenize("1,,,,___,____,,__,,2__,,,__") == [HyInteger(12)]
    assert (tokenize("_1,,,,___,____,,__,,2__,,,__") ==
            [HySymbol("_1,,,,___,____,,__,,2__,,,__")])
    assert (tokenize("1,,,,___,____,,__,,2__,q,__") ==
            [HySymbol("1,,,,___,____,,__,,2__,q,__")])


def test_lex_bad_attrs():
    with lexe() as execinfo:
        tokenize("1.foo")
    check_ex(execinfo, [
        '  File "<string>", line 1\n',
        '    1.foo\n',
        '    ^\n',
        'LexException: Cannot access attribute on anything other'
            ' than a name (in order to get attributes of expressions,'
            ' use `(. <expression> <attr>)` or `(.<attr> <expression>)`)\n'])

    with lexe(): tokenize("0.foo")
    with lexe(): tokenize("1.5.foo")
    with lexe(): tokenize("1e3.foo")
    with lexe(): tokenize("5j.foo")
    with lexe(): tokenize("3+5j.foo")
    with lexe(): tokenize("3.1+5.1j.foo")
    assert tokenize("j.foo")
    with lexe(): tokenize("3/4.foo")
    assert tokenize("a/1.foo")
    assert tokenize("1/a.foo")
    with lexe(): tokenize(":hello.foo")


def test_lex_line_counting():
    """ Make sure we can count lines / columns """
    entry = tokenize("(foo (one two))")[0]

    assert entry.start_line == 1
    assert entry.start_column == 1

    assert entry.end_line == 1
    assert entry.end_column == 15

    entry = entry[1]
    assert entry.start_line == 1
    assert entry.start_column == 6

    assert entry.end_line == 1
    assert entry.end_column == 14


def test_lex_line_counting_multi():
    """ Make sure we can do multi-line tokenization """
    entries = tokenize("""
(foo (one two))
(foo bar)
""")

    entry = entries[0]

    assert entry.start_line == 2
    assert entry.start_column == 1

    assert entry.end_line == 2
    assert entry.end_column == 15

    entry = entries[1]
    assert entry.start_line == 3
    assert entry.start_column == 1

    assert entry.end_line == 3
    assert entry.end_column == 9


def test_lex_line_counting_multi_inner():
    """ Make sure we can do multi-line tokenization (inner) """
    entry = tokenize("""(foo
    bar)""")[0]
    inner = entry[0]

    assert inner.start_line == 1
    assert inner.start_column == 2

    inner = entry[1]

    assert inner.start_line == 2
    assert inner.start_column == 5


def test_dicts():
    """ Ensure that we can tokenize a dict. """
    objs = tokenize("{foo bar bar baz}")
    assert objs == [HyDict(["foo", "bar", "bar", "baz"])]

    objs = tokenize("(bar {foo bar bar baz})")
    assert objs == [HyExpression([HySymbol("bar"),
                                  HyDict(["foo", "bar",
                                          "bar", "baz"])])]

    objs = tokenize("{(foo bar) (baz quux)}")
    assert objs == [HyDict([
        HyExpression([HySymbol("foo"), HySymbol("bar")]),
        HyExpression([HySymbol("baz"), HySymbol("quux")])
    ])]


def test_sets():
    """ Ensure that we can tokenize a set. """
    objs = tokenize("#{1 2}")
    assert objs == [HySet([HyInteger(1), HyInteger(2)])]
    objs = tokenize("(bar #{foo bar baz})")
    assert objs == [HyExpression([HySymbol("bar"),
                                  HySet(["foo", "bar", "baz"])])]

    objs = tokenize("#{(foo bar) (baz quux)}")
    assert objs == [HySet([
        HyExpression([HySymbol("foo"), HySymbol("bar")]),
        HyExpression([HySymbol("baz"), HySymbol("quux")])
    ])]

    # Duplicate items in a literal set should be okay (and should
    # be preserved).
    objs = tokenize("#{1 2 1 1 2 1}")
    assert objs == [HySet([HyInteger(n) for n in [1, 2, 1, 1, 2, 1]])]
    assert len(objs[0]) == 6

    # https://github.com/hylang/hy/issues/1120
    objs = tokenize("#{a 1}")
    assert objs == [HySet([HySymbol("a"), HyInteger(1)])]


def test_nospace():
    """ Ensure we can tokenize without spaces if we have to """
    entry = tokenize("(foo(one two))")[0]

    assert entry.start_line == 1
    assert entry.start_column == 1

    assert entry.end_line == 1
    assert entry.end_column == 14

    entry = entry[1]
    assert entry.start_line == 1
    assert entry.start_column == 5

    assert entry.end_line == 1
    assert entry.end_column == 13


def test_escapes():
    """ Ensure we can escape things """
    entry = tokenize(r"""(foo "foo\n")""")[0]
    assert entry[1] == "foo\n"

    entry = tokenize(r"""(foo r"foo\s")""")[0]
    assert entry[1] == r"foo\s"


def test_unicode_escapes():
    """Ensure unicode escapes are handled correctly"""
    s = r'"a\xac\u1234\u20ac\U00008000"'
    assert len(s) == 29
    entry = tokenize(s)[0]
    assert len(entry) == 5
    assert [ord(x) for x in entry] == [97, 172, 4660, 8364, 32768]


def test_complex():
    """Ensure we tokenize complex numbers properly"""
    # This is a regression test for #143
    entry = tokenize("(1j)")[0][0]
    assert entry == HyComplex("1.0j")
    entry = tokenize("(j)")[0][0]
    assert entry == HySymbol("j")


def test_tag_macro():
    """Ensure tag macros are handled properly"""
    entry = tokenize("#^()")
    assert entry[0][0] == HySymbol("dispatch-tag-macro")
    assert entry[0][1] == HyString("^")
    assert len(entry[0]) == 3


def test_lex_comment_382():
    """Ensure that we can tokenize sources with a comment at the end"""
    entry = tokenize("foo ;bar\n;baz")
    assert entry == [HySymbol("foo")]


def test_discard():
    """Check that discarded terms are removed properly."""
    # empty
    assert tokenize("") == []
    # single
    assert tokenize("#_1") == []
    # multiple
    assert tokenize("#_1 #_2") == []
    assert tokenize("#_1 #_2 #_3") == []
    # nested discard
    assert tokenize("#_ #_1 2") == []
    assert tokenize("#_ #_ #_1 2 3") == []
    # trailing
    assert tokenize("0") == [0]
    assert tokenize("0 #_1") == [0]
    assert tokenize("0 #_1 #_2") == [0]
    # leading
    assert tokenize("2") == [2]
    assert tokenize("#_1 2") == [2]
    assert tokenize("#_0 #_1 2") == [2]
    assert tokenize("#_ #_0 1 2") == [2]
    # both
    assert tokenize("#_1 2 #_3") == [2]
    assert tokenize("#_0 #_1 2 #_ #_3 4") == [2]
    # inside
    assert tokenize("0 #_1 2") == [0, 2]
    assert tokenize("0 #_1 #_2 3") == [0, 3]
    assert tokenize("0 #_ #_1 2 3") == [0, 3]
    # in HyList
    assert tokenize("[]") == [HyList([])]
    assert tokenize("[#_1]") == [HyList([])]
    assert tokenize("[#_1 #_2]") == [HyList([])]
    assert tokenize("[#_ #_1 2]") == [HyList([])]
    assert tokenize("[0]") == [HyList([HyInteger(0)])]
    assert tokenize("[0 #_1]") == [HyList([HyInteger(0)])]
    assert tokenize("[0 #_1 #_2]") == [HyList([HyInteger(0)])]
    assert tokenize("[2]") == [HyList([HyInteger(2)])]
    assert tokenize("[#_1 2]") == [HyList([HyInteger(2)])]
    assert tokenize("[#_0 #_1 2]") == [HyList([HyInteger(2)])]
    assert tokenize("[#_ #_0 1 2]") == [HyList([HyInteger(2)])]
    # in HySet
    assert tokenize("#{}") == [HySet()]
    assert tokenize("#{#_1}") == [HySet()]
    assert tokenize("#{0 #_1}") == [HySet([HyInteger(0)])]
    assert tokenize("#{#_1 0}") == [HySet([HyInteger(0)])]
    # in HyDict
    assert tokenize("{}") == [HyDict()]
    assert tokenize("{#_1}") == [HyDict()]
    assert tokenize("{#_0 1 2}") == [HyDict([HyInteger(1), HyInteger(2)])]
    assert tokenize("{1 #_0 2}") == [HyDict([HyInteger(1), HyInteger(2)])]
    assert tokenize("{1 2 #_0}") == [HyDict([HyInteger(1), HyInteger(2)])]
    # in HyExpression
    assert tokenize("()") == [HyExpression()]
    assert tokenize("(#_foo)") == [HyExpression()]
    assert tokenize("(#_foo bar)") == [HyExpression([HySymbol("bar")])]
    assert tokenize("(foo #_bar)") == [HyExpression([HySymbol("foo")])]
    assert tokenize("(foo :bar 1)") == [HyExpression([HySymbol("foo"), HyKeyword("bar"), HyInteger(1)])]
    assert tokenize("(foo #_:bar 1)") == [HyExpression([HySymbol("foo"), HyInteger(1)])]
    assert tokenize("(foo :bar #_1)") == [HyExpression([HySymbol("foo"), HyKeyword("bar")])]
    # discard term with nesting
    assert tokenize("[1 2 #_[a b c [d e [f g] h]] 3 4]") == [
        HyList([HyInteger(1), HyInteger(2), HyInteger(3), HyInteger(4)])
    ]
    # discard with other prefix syntax
    assert tokenize("a #_'b c") == [HySymbol("a"), HySymbol("c")]
    assert tokenize("a '#_b c") == [HySymbol("a"), HyExpression([HySymbol("quote"), HySymbol("c")])]
    assert tokenize("a '#_b #_c d") == [HySymbol("a"), HyExpression([HySymbol("quote"), HySymbol("d")])]
    assert tokenize("a '#_ #_b c d") == [HySymbol("a"), HyExpression([HySymbol("quote"), HySymbol("d")])]


def test_lex_exception_filtering(capsys):
    """Confirm that the exception filtering works for lexer errors."""

    # First, test for PrematureEndOfInput
    with peoi() as execinfo:
        tokenize(" \n (foo")
    check_trace_output(capsys, execinfo, [
        '  File "<string>", line 2',
        '    (foo',
        '       ^',
        'PrematureEndOfInput: Premature end of input'])

    # Now, for a generic LexException
    with lexe() as execinfo:
        tokenize("  \n\n  1.foo   ")
    check_trace_output(capsys, execinfo, [
        '  File "<string>", line 3',
        '    1.foo',
        '    ^',
        'LexException: Cannot access attribute on anything other'
            ' than a name (in order to get attributes of expressions,'
            ' use `(. <expression> <attr>)` or `(.<attr> <expression>)`)'])