Remove Forward definitions where possible. #22875
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pyparsing.Forward only needs to be used for mutually recursive mathtext elements; others can be defined directly (using `=` instead of `<<=`). This speeds up ``` MPLBACKEND=agg python -c 'import time; from pylab import *; from matplotlib.tests.test_mathtext import math_tests; fig = figure(figsize=(3, 10)); fig.text(0, 0, "\n".join(filter(None, math_tests)), size=6); start = time.perf_counter(); [fig.canvas.draw() for _ in range(10)]; print((time.perf_counter() - start) / 10)' ``` by around 6%.
| p.non_math + ZeroOrMore(p.math_string + p.non_math) + StringEnd() | ||
| ) | ||
| set_names_and_parse_actions() # for leaf definitions. |
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Why do we need to call this 3x?
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This is because e.g. float_literal is defined at the very top (root definition), but then gets used as float_literal("rulesize") in the mutually recursive definitions block; this creates a copy of float_literal and adds a name ("rulesize") to it. Therefore, float_literal must already have its parse action set at that point. So it's not possible to set all parse actions at the end after all definitions. (It's also not possible to set the parse actions all together after declaring all blocks (as was done before), as the point of the PR is exactly to not have to declare blocks anymore.)
Technically, this does mean that the same parse action gets re-set three times on the root elements and two times on the mutually recursive elements, but this isn't a problem at all, afaict.
pyparsing.Forward only needs to be used for mutually recursive mathtext
elements; others can be defined directly (using
=instead of<<=).This speeds up
by around 6%.
(This was the first suggestion in #20821 (comment).)
PR Summary
PR Checklist
Tests and Styling
pytestpasses).flake8-docstringsand runflake8 --docstring-convention=all).Documentation
doc/users/next_whats_new/(follow instructions in README.rst there).doc/api/next_api_changes/(follow instructions in README.rst there).