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Substitution variables

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This commit is contained in:
Darren Burns
2022-02-02 15:49:16 +00:00
parent ac9e3cdfff
commit 65a6b8d261
5 changed files with 140 additions and 34 deletions
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6
examples/basic.css
View File

@@ -1,8 +1,10 @@
/* CSS file for basic.py */
$primary: #20639b;
App > View {
docks: side=left/1;
text: on #20639b;
text: on $primary;
}
Widget:hover {
@@ -34,7 +36,7 @@ Widget:hover {
}
#content {
text: white on #20639b;
text: white on $primary;
border-bottom: hkey #0f2b41;
}

4
src/textual/css/errors.py
View File

@@ -9,6 +9,10 @@ class DeclarationError(Exception):
super().__init__(message)
class UnresolvedVariableError(NameError):
pass
class StyleTypeError(TypeError):
pass

107
src/textual/css/parse.py
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@@ -1,17 +1,14 @@
from __future__ import annotations
import itertools
from collections import defaultdict
from functools import lru_cache
from itertools import dropwhile
from typing import Iterator, Iterable
from rich import print
from functools import lru_cache
from typing import Iterator, Iterable
from .styles import Styles
from .tokenize import tokenize, tokenize_declarations, Token
from .tokenizer import EOFError
from textual.css.errors import UnresolvedVariableError
from ._styles_builder import StylesBuilder, DeclarationError
from .model import (
Declaration,
RuleSet,
@@ -20,8 +17,9 @@ from .model import (
SelectorSet,
SelectorType,
)
from ._styles_builder import StylesBuilder, DeclarationError
from .styles import Styles
from .tokenize import tokenize, tokenize_declarations, Token
from .tokenizer import EOFError
SELECTOR_MAP: dict[str, tuple[SelectorType, tuple[int, int, int]]] = {
"selector": (SelectorType.TYPE, (0, 0, 1)),
@@ -37,7 +35,6 @@ SELECTOR_MAP: dict[str, tuple[SelectorType, tuple[int, int, int]]] = {
@lru_cache(maxsize=1024)
def parse_selectors(css_selectors: str) -> tuple[SelectorSet, ...]:
tokens = iter(tokenize(css_selectors, ""))
get_selector = SELECTOR_MAP.get
@@ -84,7 +81,6 @@ def parse_selectors(css_selectors: str) -> tuple[SelectorSet, ...]:
def parse_rule_set(tokens: Iterator[Token], token: Token) -> Iterable[RuleSet]:
get_selector = SELECTOR_MAP.get
combinator: CombinatorType | None = CombinatorType.DESCENDENT
selectors: list[Selector] = []
@@ -208,21 +204,84 @@ def parse_declarations(css: str, path: str) -> Styles:
return styles_builder.styles
# def _with_resolved_variables(tokens: Iterable[Token]) -> Iterable[Token]:
# variables: dict[str, list[Token]] = defaultdict(list)
# for token in tokens:
# token = next(tokens, None)
# if token is None:
# break
# if token.name == "variable_name":
# variable_name = token.value[1:-1] # Trim the $ and the :, i.e. "$x:" -> "x"
# # At this point, we need to tokenize the variable value, as when we pass
# # the Declarations to the style builder, types must be known (e.g. Scalar vs Duration)
# variables[variable_name] =
def _is_whitespace(token: Token) -> bool:
return token.name == "whitespace"
def _unresolved(
variable_name: str, location: tuple[int, int]
) -> UnresolvedVariableError:
return UnresolvedVariableError(
f"variable ${variable_name} is not defined. "
f"attempted reference at location {location!r}"
)
def substitute_references(tokens: Iterator[Token]) -> Iterable[Token]:
"""Replace variable references with values by substituting variable reference
tokens with the tokens representing their values.
Args:
tokens (Iterator[Token]): Iterator of Tokens which may contain tokens
with the name "variable_ref".
Returns:
Iterable[Token]: Yields Tokens such that any variable references (tokens where
token.name == "variable_ref") have been replaced with the tokens representing
the value. In other words, an Iterable of Tokens similar to the original input,
but with variables resolved.
"""
variables: dict[str, list[Token]] = defaultdict(list)
while tokens:
token = next(tokens, None)
if token is None:
break
if token.name == "variable_name":
variable_name = token.value[1:-1] # Trim the $ and the :, i.e. "$x:" -> "x"
yield token
# Lookahead for the variable value tokens
while True:
token = next(tokens, None)
if not token:
break
if token.name != "variable_value_end":
# For variables referring to other variables
if token.name == "variable_ref":
ref_name = token.value[1:]
if ref_name in variables:
variables[variable_name].extend(variables[ref_name])
variable_tokens = dropwhile(
_is_whitespace,
variables[ref_name],
)
yield from variable_tokens
else:
raise _unresolved(
variable_name=ref_name, location=token.location
)
else:
variables[variable_name].append(token)
yield token
else:
yield token
break
elif token.name == "variable_ref":
variable_name = token.value[1:] # Trim the $, so $x -> x
if variable_name in variables:
variable_tokens = dropwhile(
_is_whitespace,
variables[variable_name],
)
yield from variable_tokens
else:
raise _unresolved(variable_name=variable_name, location=token.location)
else:
yield token
def parse(css: str, path: str) -> Iterable[RuleSet]:
tokens = iter((tokenize(css, path)))
tokens = iter(substitute_references(tokenize(css, path)))
while True:
token = next(tokens, None)
if token is None:

3
src/textual/css/tokenizer.py
View File

@@ -1,9 +1,8 @@
from __future__ import annotations
from typing import NamedTuple
import re
from typing import NamedTuple
from rich import print
import rich.repr

54
tests/css/test_parse.py
View File

@@ -1,19 +1,61 @@
import pytest
from rich.color import Color, ColorType
# from textual.css.parse import _resolve_variables
from textual.css.errors import UnresolvedVariableError
from textual.css.parse import substitute_references
from textual.css.scalar import Scalar, Unit
from textual.css.stylesheet import Stylesheet, StylesheetParseError
from textual.css.tokenize import tokenize
from textual.css.tokenizer import Token
from textual.css.transition import Transition
from textual.layouts.dock import DockLayout
# class TestVariableResolution:
# def test_resolve_single_variable(self):
# css = "$x: 1;"
# variables = _resolve_variables(tokenize(css, ""))
# assert variables == {"x": }
class TestVariableReferenceSubstitution:
def test_simple_reference(self):
css = "$x: 1; #some-widget{border: $x;}"
variables = substitute_references(tokenize(css, ""))
assert list(variables) == [
Token(name='variable_name', value='$x:', path='', code=css, location=(0, 0)),
Token(name='whitespace', value=' ', path='', code=css, location=(0, 3)),
Token(name='number', value='1', path='', code=css, location=(0, 4)),
Token(name='variable_value_end', value=';', path='', code=css, location=(0, 5)),
Token(name='whitespace', value=' ', path='', code=css, location=(0, 6)),
Token(name='selector_start_id', value='#some-widget', path='', code=css, location=(0, 7)),
Token(name='declaration_set_start', value='{', path='', code=css, location=(0, 19)),
Token(name='declaration_name', value='border:', path='', code=css, location=(0, 20)),
Token(name='whitespace', value=' ', path='', code=css, location=(0, 27)),
Token(name='number', value='1', path='', code=css, location=(0, 4)),
Token(name='declaration_end', value=';', path='', code=css, location=(0, 30)),
Token(name='declaration_set_end', value='}', path='', code=css, location=(0, 31))
]
def test_undefined_variable(self):
css = ".thing { border: $not-defined; }"
with pytest.raises(UnresolvedVariableError):
list(substitute_references(tokenize(css, "")))
def test_transitive_reference(self):
css = "$x: 1\n$y: $x\n.thing { border: $y }"
assert list(substitute_references(tokenize(css, ""))) == [
Token(name='variable_name', value='$x:', path='', code=css, location=(0, 0)),
Token(name='whitespace', value=' ', path='', code=css, location=(0, 3)),
Token(name='number', value='1', path='', code=css, location=(0, 4)),
Token(name='variable_value_end', value='\n', path='', code=css, location=(0, 5)),
Token(name='variable_name', value='$y:', path='', code=css, location=(1, 0)),
Token(name='whitespace', value=' ', path='', code=css, location=(1, 3)),
Token(name='number', value='1', path='', code=css, location=(0, 4)),
Token(name='variable_value_end', value='\n', path='', code=css, location=(1, 6)),
Token(name='selector_start_class', value='.thing', path='', code=css, location=(2, 0)),
Token(name='whitespace', value=' ', path='', code=css, location=(2, 6)),
Token(name='declaration_set_start', value='{', path='', code=css, location=(2, 7)),
Token(name='whitespace', value=' ', path='', code=css, location=(2, 8)),
Token(name='declaration_name', value='border:', path='', code=css, location=(2, 9)),
Token(name='whitespace', value=' ', path='', code=css, location=(2, 16)),
Token(name='number', value='1', path='', code=css, location=(0, 4)),
Token(name='whitespace', value=' ', path='', code=css, location=(2, 19)),
Token(name='declaration_set_end', value='}', path='', code=css, location=(2, 20))
]
class TestParseLayout: