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Runtime evaluation: Difference between revisions
Added PicoLisp
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print eval($code);
</lang>
=={{header|PicoLisp}}==
In PicoLisp there is a formal equivalence of code and data. Almost any peace of
data is potentially executable. PicoLisp has three internal data types: Numbers,
symbols and lists. Though in certain contexts (e.g. GUI objects) also atomic
data (numbers and symbols) are evaluated as code entities, a typical executable
item is a list.
The PicoLisp reference distinguishes between two terms: An 'exe' (expression) is
an executable list, with a function as the first element, followed by arguments.
A 'prg' (program) is a list of 'exe's, to be executed sequentially.
'exe's and 'prg's are implicit in the whole runtime system. For example, the
body of a function is a 'prg', the "true" branch of an 'if' call is an 'exe',
while the "false" branch again is a 'prg'.
For explicit execution, an 'exe' can be evaluated by passing it to the function
'[http://software-lab.de/doc/refE.html#eval eval]', while a 'prg' can be handled
by '[http://software-lab.de/doc/refR.html#run run]'.
As PicoLisp uses exclusively dynamic binding, any 'exe' or 'prg' can be executed
in arbitrary contexts. The environmet can be controlled in any conceivable way,
through implicit function parameter bindings, or explicitly with the aid of
functions like '[http://software-lab.de/doc/refB.html#bind bind]',
'[http://software-lab.de/doc/refL.html#let let]' or
'[http://software-lab.de/doc/refJ.html#job job]'.
=={{header|Ruby}}==
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