5.18 The Python Library: pylispe

pylispe

This library is both a LispE library and a python library. It offers the possibility either to execute python code in LispE or LispE code in python, using the same library.

From a LispE point of view

Here are the functions that are exposed by pylispe:

(deflib python() ; create a python interpreter for LispE)
(deflib python_run(py code (variable "") (timeout -1)) ; run a piece of code and returns the result in an optional variable, a timeout can be set as well)
(deflib python_runmodule(py name code (variable "")) ;run a module, with the final value in an optional variable)
deflib python_getmodule(py name (variable "")) ; load a python module);
deflib python_runfile(py path) ; execute a Python file)
deflib python_setpath(py path) ; set a path to find Python libraries)
deflib python_import(py path) ; import a module or a library)
deflib python_execute(py name arguments) ; execute a function)
deflib python_simple(py code) ; use python_simple to execute code)
deflib python_close(py) ; close the python interpreter)

Example

; This code executes some Python instructions

(use 'pylispe)

; we create a python intepreter
(setq py (python))

;We execute some code
(setq res (python_run py "i = 100 + 20" "i"))
(println res) ; 120 since the calculus was stored in "i" and we ask "i" as the return variable

(python_run py "print('Within:',i)")

; We define a Python function
; as a LispE string
(setq myFunc
`def toto(i):
   return i+10;
`
)

; we store our function definition
(python_run py myFunc)

; which we can execute and retrieve a result from it
(println (python_execute py "toto" '(11)))

From a Python point of view

Here the code that can be executed from within Python:

# This code executes some LispE code within Python

import pylispe

# we create a lisp interpreter
a=pylispe.lisp()

# We load the current file

print(a.load("called_in_python.lisp"))

# an evaluation
print(a.eval("(setq d 10)"))


# We can actually call an instruction or an operator directly
# Note the '".."' structure to pass strings to LispE, while
# atoms are passed as simple strings: the 'd' is the atom
# that was created above in the 'setq' instruction
print(a.execute("+", '"test"', 'd'))

# We can also use the add function that has been implemented in called.lisp
# The 'd' is again the one that was declared above with the value 10


print(a.execute("add", "d", 31.654))