A recursive pattern matching strip, useful for scanning through structured text like source code, checking for structure-level patterns.
With PATN you can define expressions to match against structures within the text and then apply a conditional to it.
Simply, expressions are REGEX (PCRE-like, a la Python) where you set out a simple matche or specify match group(s). The expressions are evaluated per-line of input text and are applied multiple times (currently there is no facilities to check across lines).
When performing a match, you can define the following conditions:
| Operation | Alt | Notes |
|---|---|---|
skip |
>> |
apply only the expression (and store results for next expression) |
count |
# |
Print out number of successful applications of expression (WIP) |
M[idx]==/!=M[idx] |
For the current expression (which contains match groups), check equality of one group to another group | |
M[idx]==/!='string' |
For the current expression (which contains match groups), check equality of one group to a string | |
M[idx]==/!=P[idx] |
For the current expression (which contains match groups), check equality of one group to the result of the previous expression | |
<num or range>:M[idx]... |
For the current expression, set a constraint on which successful applications of the expression the condition should be applied to |
For M and P there are also control expressions that set out, given a collection of matches, if the conditional should apply to all, any, or one (this is still WIP).
This work is released under the ISC License.