This is an reimplementation of pyscheme using various supported C scheme libraries for speed. If no C scheme libraries are available it will fall back to the much slower pyscheme library.
It was designed to offer faster parsing of Thousand Parsec TPCL programs such as:
- tpserver-py
- tpclient-py*
- tpruledev
It is written in pure python using the python-ctypes library. This library comes with python2.5 (it can be downloaded for earlier versions of python).
Planned supporting C scheme libraries (bold are already supported): http://community.schemewiki.org/?scheme-faq-standards#implementations
- guile
- mzscheme
- STklos - http://www.stklos.org/
- Chicken
- Elk - http://sam.zoy.org/elk/
import schemepy as scheme
# Create a new scheme compiler A compiler converts text strings into
# an internal format, this allows you to compile something once and
# then evaluate it multiple times This is more efficent as parsing and
# compiling the text takes up the most significant amount of time.
c = scheme.Compiler()
<internal scheme structure> = c(<string>)
# Calling the compiler can throw a scheme.CompilerException, these have the
# following attributes,
# e.lineno - the line on which the error occured
# e.position - the position the error was detected at
# e.message - a human readable message why this is not valid
# Create a new scheme empty vm
vm = scheme.VM()
# You can then install new functions into the vm using the following
#
# Functions must take <internal scheme structure> arguments and return a
# <internal scheme structure>.
#
# The function MUST NOT store any of the given structures.
vm.install_function(<name>, <python callable>)
# You can then do something like
#
# def myadd(a, b):
# a = vm.fromscheme(a)
# b = vm.fromscheme(b)
#
# return vm.toscheme(a+b)
# You can also have autoconversion by doing the following, then the above
# function could read
#
# def myadd(a, b):
# return a+b
vm.install_function(<name>, <python callable>, autoconvert=True)
# To evaluate scheme code just use the eval function. It must have been
# previously parsed by the scheme parser.
<internal scheme structure> = vm.eval(<internal scheme structure>)
# Get the python type
<internal scheme structure>.type()
# Convert to a python object - with complex objects this is only does one level.
<internal scheme structure>.topython()
# You can also call functions in the scheme enviroment directly
<internal scheme structure> = i.environment.cdr(<internal scheme structure>)
<internal scheme structure> = i.environment.car(<internal scheme structure>)
# The scheme library also provides some convience functions.
# These two functions allow you to convert from the internal scheme structures
# to python types.
# The functions will automatically map the following types,
# - bool
# - int
# - float
# - complex
# - list
# - dictionary
<internal scheme object> = scheme.toscheme(<python object>)
<python object> = scheme.topython(<internal scheme object>)For further and detailed information of the interface, see docs/html/front_end.html.
This package is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.
This package is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this package; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA