Use delimited list to parse substack

ksunden · devRD · commit a48e51b7caf8 · 2023-07-09T22:18:21.000+05:30
diff --git a/lib/matplotlib/_mathtext.py b/lib/matplotlib/_mathtext.py
@@ -14,7 +14,7 @@
 
 import numpy as np
 from pyparsing import (
-    Empty, Forward, Literal, NotAny, oneOf, OneOrMore, Optional,
+    Empty, Forward, Literal, NotAny, oneOf, OneOrMore, Optional, delimited_list,
     ParseBaseException, ParseException, ParseExpression, ParseFatalException,
     ParserElement, ParseResults, QuotedString, Regex, StringEnd, ZeroOrMore,
     pyparsing_common)
@@ -1700,6 +1700,7 @@ def names(elt):
     csname = expr.split("{", 1)[0]
     err = (csname + "".join("{%s}" % name for name in names(args))
            if expr == csname else expr)
+    print(csname, args, err)
     return csname - (args | Error(f"Expected {err}"))
 
 
@@ -1855,7 +1856,7 @@ def csnames(group, names):
             + r"|\\(?:{})(?![A-Za-z])".format(
                 "|".join(map(re.escape, tex2uni)))
         )("sym").leaveWhitespace()
-        p.unknown_symbol = Regex(r"\\[A-Za-z]*")("name")
+        p.unknown_symbol = Regex(r"\\[A-Za-z]+")("name")
 
         p.font           = csnames("font", self._fontnames)
         p.start_group    = Optional(r"\math" + oneOf(self._fontnames)("font")) + "{"
@@ -1935,7 +1936,7 @@ def csnames(group, names):
         p.operatorname = cmd(r"\operatorname", "{" + ZeroOrMore(p.simple)("name") + "}")
 
         p.substack <<= cmd(
-            r"\substack", OneOrMore(p.required_group("value")))
+            r"\substack", "{"+delimited_list(OneOrMore(p.token), delim="\\\\", combine=True)("parts")+"}")
 
         p.placeable     <<= (
             p.accent     # Must be before symbol as all accents are symbols
@@ -1952,8 +1953,8 @@ def csnames(group, names):
             | p.underset
             | p.sqrt
             | p.overline
-            | p.text
             | p.substack
+            | p.text
         )
 
         p.auto_delim    <<= (
@@ -1976,6 +1977,7 @@ def csnames(group, names):
 
         # To add space to nucleus operators after sub/superscripts
         self._in_subscript_or_superscript = False
+        self.p = p
 
     def parse(self, s, fonts_object, fontsize, dpi):
         """
@@ -2604,13 +2606,17 @@ def auto_delim(self, s, loc, toks):
             toks["right"])
 
     def substack(self, s, loc, toks):
+        print(list(toks.keys()))
+        print(toks["parts"])
+        parts = toks["parts"].split("\\\\")
+        print(parts)
         state = self.get_state()
         thickness = state.get_current_underline_thickness()
         vlist = []
 
-        max_width = max(map(lambda c: c.width, toks[1:]))
+        max_width = max(map(lambda c: c.width, parts))
 
-        for sub in toks[1:]:
+        for sub in parts:
             cp = HCentered([sub])
             cp.hpack(max_width, 'exactly')
             vlist.append(cp)
