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=====
TermL
=====
TermL ("term-ell") is the Term Language, a small expression-based language for
representing arbitrary data in a simple structured format. It is ideal for
expressing abstract syntax trees (ASTs) and other kinds of primitive data
trees.
Creating Terms
==============
::
>>> from terml.nodes import termMaker as t
>>> t.Term()
term('Term')
That's it! We've created an empty term, `Term`, with nothing inside.
::
>>> t.Num(1)
term('Num(1)')
>>> t.Outer(t.Inner())
term('Outer(Inner)')
We can see that terms are not just `namedtuple` lookalikes. They have their
own internals and store data in a slightly different and more structured way
than a normal tuple.
Parsing Terms
=============
Parsley can parse terms from streams. Terms can contain any kind of parseable
data, including other terms. Returning to the ubiquitous calculator example::
add = Add(:x, :y) -> x + y
Here this rule matches a term called `Add` which has two components, bind
those components to a couple of names (`x` and `y`), and return their sum. If
this rule were applied to a term like `Add(3, 5)`, it would return 8.
Terms can be nested, too. Here's an example that performs a slightly contrived
match on a negated term inside an addition::
add_negate = Add(:x, Negate(:y)) -> x - y
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