crox

crox is a light-weight general-purpose macro expander.

It is a streaming parser that processes each line only once. This means that functions and variables need to be defined before they are used.

Install

Install through PyPI:

pip install crox

This will install the command line tool crox. Can also be called using python -m crox.

Commands

Each command is prefixed by :. This can be changed using the -e option.

Define variable

Variables can be defined and re-defined at any time:

:define <variable name> <value>

Ex:

:define ABC 100

Reference variable

$<variable name>
${<variable name>}

Ex:

Variable $ABC or ${ABC}.

Define function

Functions can be defined and re-defined at any time:

:begin <function name> <arg name 1> <arg name 2> ...
<contents>
:end

Ex:

:begin foo x
Calling foo with x=$x.
:end

Call function

:call <function name> <arg 1> <arg 2> ...

Ex:

:call foo 100

Include file

Includes another file in-place that uses and can modify the same state machine (equivalent of copy-pasting in the other file at this location):

:include <filename>

Ex:

:include inc.crox

Define variable through expression

You can also define variables based on previous variables:

:define-eval <variable name> <expression (rest of the line)>

Ex:

:define X 100
:define-eval Y $X + 100

Example

Imagine a source file test.crox.txt:

:define abc 100
:begin foo x y
Calling foo with $x and $y, using global $abc.
:end
This is an example

:call foo 10 test
:define abc 200
:call foo 20 abc

Now call:

crox test.crox.txt

Will produce the following to standard output:

This is an example

Calling foo with 10 and test, using global 100.
Calling foo with 20 and abc, using global 200.