Fix error with pyparsing 3

timhoffm · timhoffm · commit ba51894f5f0a · 2021-10-24T22:53:25.000+02:00
- Code suggestion taken from matplotlib#21448 - Removed all pyparsing pinning. If this runs through CI, the fix is proven to be working.
diff --git a/lib/matplotlib/_mathtext.py b/lib/matplotlib/_mathtext.py
@@ -13,7 +13,7 @@
 
 import numpy as np
 from pyparsing import (
-    Combine, Empty, FollowedBy, Forward, Group, Literal, oneOf, OneOrMore,
+    Combine, Empty, Forward, Group, Literal, oneOf, OneOrMore,
     Optional, ParseBaseException, ParseFatalException, ParserElement,
     ParseResults, QuotedString, Regex, StringEnd, Suppress, ZeroOrMore)
 
@@ -2044,7 +2044,7 @@ def __init__(self):
         p.accentprefixed <<= Suppress(p.bslash) + oneOf(self._accentprefixed)
         p.symbol_name   <<= (
             Combine(p.bslash + oneOf(list(tex2uni)))
-            + FollowedBy(Regex("[^A-Za-z]").leaveWhitespace() | StringEnd())
+            + Suppress(Regex("(?=[^A-Za-z]|$)").leaveWhitespace())
         )
         p.symbol        <<= (p.single_symbol | p.symbol_name).leaveWhitespace()
 
diff --git a/requirements/doc/doc-requirements.txt b/requirements/doc/doc-requirements.txt
@@ -13,7 +13,6 @@ ipython
 ipywidgets
 numpydoc>=0.8
 packaging>=20
-pyparsing<3.0.0
 pydata-sphinx-theme>=0.6.0
 sphinxcontrib-svg2pdfconverter>=1.1.0
 sphinx-gallery>=0.10
diff --git a/requirements/testing/all.txt b/requirements/testing/all.txt
@@ -2,7 +2,6 @@
 
 certifi
 coverage
-pyparsing<3.0.0
 pytest!=4.6.0,!=5.4.0
 pytest-cov
 pytest-rerunfailures
diff --git a/setup.py b/setup.py
@@ -326,7 +326,7 @@ def make_release_tree(self, base_dir, files):
         "numpy>=1.17",
         "packaging>=20.0",
         "pillow>=6.2.0",
-        "pyparsing>=2.2.1,<3.0.0",
+        "pyparsing>=2.2.1",
         "python-dateutil>=2.7",
     ] + (
         # Installing from a git checkout.
