mpl.mathtext.ParserElement.setParseAction¶

ParserElement.setParseAction(*fns, **kwargs)[source]¶

Define action to perform when successfully matching parse element definition. Parse action fn is a callable method with 0-3 arguments, called as C{fn(s,loc,toks)}, C{fn(loc,toks)}, C{fn(toks)}, or just C{fn()}, where:

• s = the original string being parsed (see note below)
• loc = the location of the matching substring
• toks = a list of the matched tokens, packaged as a C{L{ParseResults}} object

If the functions in fns modify the tokens, they can return them as the return value from fn, and the modified list of tokens will replace the original. Otherwise, fn does not need to return any value.

Optional keyword arguments:

• callDuringTry = (default=False) indicate if parse action should be run during lookaheads and alternate testing

Note: the default parsing behavior is to expand tabs in the input string before starting the parsing process. See L{I{parseString}<parseString>} for more information on parsing strings containing C{<TAB>}s, and suggested methods to maintain a consistent view of the parsed string, the parse location, and line and column positions within the parsed string.