recognizers 1.3.2
A collection of recognizers
- raw README.md
- raw Recognizer.4th
- raw Stack.4th
- raw literacy.4th
- raw package.4th
- raw rec-name.4th
- raw rec-num.4th
- raw rec-time.4th
- raw rec-word.4th
Recognizers
Matthias Trute mtrute@web.de Version 1.3.2 - 2016-10-11
This package is a collection of recognizer examples. To play with them a simple implementation for (old) gforth and VFX is included. These words are not (yet) able to compile code or are otherwise integrated into the underlying system.
Many examples contain test units that illustrate what the recognizer is supposed to do.
Recognizer.4th
This file in combination with Stack.4th
gives a
playground for making experiments with recognizers. It
has been tested with gforth versions that currently
come with the linux distributions and MPE's vfxlin (a
random old version from 2014).
rec-num.4th
This file contains four recognizers. They deal with
numbers in various formats and use >NUMBER
for the
actual number conversion.
rec:char ( addr len -- n r:num | r:fail)
Forth 2012 defined the 'c' syntax for single characters.
That means that char c
or [char] c
can be replaced
with 'c'
.
rec:snum ( addr len -- n r:num | r:fail)
This recognizer can handle single cell numbers. It honors the number prefixes and the sign characters + and - in any order.
rec:dnum ( addr len -- d r:dnum | r:fail)
This recognizer handles double cell numbers. It accepts the standard number format: digits with a trailing dot in addition to the prefix and sign character.
These three recognizers are combined in the rec:num
recognizer that may be used to handle all number formats
in one call.
rec-word.4th
This file contains a dictionary lookup recognizer. It uses
FIND
for the actual work thus uses the search order if
present.
rec-name.4th
Another dictionary lookup recognizer. This one does not
depend on FIND
and searches the standard forth wordlist
only. It returns name tokens instead of the usual
execution tokens as well.
It requires TRAVERSE-WORDLIST
and the NAME>x
words
from Forth 2012 to work. From the future, quotations are
used too.
literacy.4th
Simple formatting of source code in the spirit von Don Knuth' literate programming. You can combine the real source code and its documentation in one file that the standard forth interpreter can handle directly.
Actually testing this recognizer requires a Forth that supports recognizers already.
Author: Julian Fondren, 2014 License: probably public domain.
rec-time.4th
check and convert for the hh:mm:ss notation returning a double cell number for the number of seconds it represents.