The original Codan compiler (because Sprunge deletes old pastes).

codan.py

#!/usr/bin/python2.5
# coding=utf8

"""
 Copyright © 2010 Codan Working Group

 Permission is hereby granted, free of charge, to any person obtaining a
 copy of this software and associated documentation files (the "Software"),
 to deal in the Software without restriction, including without limitation
 the rights to use, copy, modify, merge, publish, distribute, sublicense,
 and/or sell copies of the Software, and to permit persons to whom the
 Software is furnished to do so, subject to the following conditions:

 The above copyright notice and this permission notice shall be included in
 all copies or substantial portions of the Software.

 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 DEALINGS IN THE SOFTWARE.
"""

CC = "gcc"

import sys, os

if len(sys.argv) < 2:
    print "\033[1mUsage:\033[0m %s" % sys.argv[0],\
          "[ \033[4mCFLAGS\033[0m ... ] \033[4minfile\033[0m"
    sys.exit(0)


f = open(sys.argv[-1])
codan = filter(lambda n: n in u"«»←→αβΑΒΛא+−×÷↑=≠<≤>≥≮≯≰≱0123456789\n\t ",
               unicode("".join(f.readlines()), "utf8"))
f.close()


out = """
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <termios.h>

int main(void)
{
    int mem[10000];
    int alpha, beta, t;
"""

iomode = False  # True = %c; False = %d


i = 0

try:
    while i < len(codan):
        while codan[i] in u" \n\t":
            i += 1

        if codan[i] == u'«':             # Open loop
            out += "for (;;) {\n"
            i += 1

        elif codan[i] == u'»':           # Close loop
            out += "}\n"
            i += 1

        elif codan[i] == u'א':          # Output mode toggle
            iomode = not iomode
            i += 1

        else:                           # Three-part expression

            loperand, operator, roperand = None, None, None
        
            # Read left operand

            if codan[i] in u"0123456789":
                s = i
                while codan[i] in u"0123456789":
                    i += 1
                loperand = codan[s:i]

            elif codan[i] in u"αβΑΒΛ+−×÷":
                loperand = codan[i]
                i += 1

            else:
                print "Syntax error at %d!" % i
                sys.exit(1)

            
            # Read operator

            while codan[i] in u" \n\t":
                i += 1

            if codan[i] in u"←→↑=≠<≤>≥≮≯≰≱":
                operator = codan[i]
                i += 1

            else:
                print "Syntax error at %d!" % i
                sys.exit(1)


            # Read right operand

            while codan[i] in u" \n\t":
                i += 1
        
            if codan[i] in u"0123456789":
                s = i
                while codan[i] in u"0123456789":
                    i += 1
                roperand = codan[s:i]

            elif codan[i] in u"αβΑΒΛ+−×÷":
                roperand = codan[i]
                i += 1

            else:
                print "Syntax error at %d!" % i
                sys.exit(1)


            # Ensure arrow expressions are in x ← y form
    
            if operator == u'→':
                loperand, roperand = roperand, loperand
                operator = u'←'


            # Pase left operand
    
            if loperand in u"αβΑΒ":
                loperand = { u'α': "mem[alpha]",
                             u'β': "mem[beta]",
                             u'Α': "alpha",
                             u'Β': "beta" }[loperand]

            elif loperand == u'Λ':
                loperand, operator = '', loperand

            else:
                try:
                    loperand = int(loperand)
                    if operator == u'←':
                        loperand = "mem[%d]" % loperand
                    else:
                        loperand = str(loperand)

                except ValueError:
                    print "Syntax error!"
                    raise
        
    
            # Parse right operand

            if roperand in u"+−×÷↑":
                roperand = { u'+': "mem[alpha] + mem[beta]",
                             u'−': "mem[alpha] - mem[beta]",
                             u'×': "mem[alpha] * mem[beta]",
                             u'÷': "mem[alpha] / mem[beta]",
                             u'↑': "(int)pow((int)mem[alpha], " +\
                                   "(int)mem[beta])" }[roperand]

            elif roperand == u'Λ':
                out += 't = (int) getchar();\n' if iomode else \
                       'scanf("%d\\n", &t);\n'
                roperand = "t"

            elif roperand in u'αβΑΒ':
                roperand = { u'α': "mem[alpha]",
                             u'β': "mem[beta]",
                             u'Α': "alpha",
                             u'Β': "beta" }[roperand]

            else:
                try:
                    roperand = int(roperand)
                    roperand = str(roperand)
                except ValueError:
                    print "Syntax error!"
                    raise


            # Parse operator and emit

            if operator in u"<>=≤≥≠≮≯≰≱":
                operator = { u'=': "!=",
                             u'≠': "==",
                             u'≤': ">",
                             u'≯': ">",
                             u'≥': "<",
                             u'≮': "<",
                             u'≰': "<=",
                             u'>': "<=",
                             u'≱': ">=",
                             u'<': ">=" }[operator]

                out += "if (%s %s %s) break;\n" % (loperand,
                                                   operator,
                                                   roperand)

            elif operator == u'←':
                out += "%s = %s;\n" % (loperand, roperand)

            elif operator == u'Λ':
                if iomode:
                    out += 'printf("%%c", %s);\n' % roperand

                else:
                    out += 'printf("%%d\\n", %s);\n' % roperand

except IndexError:
    # Source file ends in whitespace
    pass


out += """
    return 0;
}
"""

# Make temporary C file and compile it

cfile = os.tempnam() + ".c"
f = open(cfile, 'w')
f.write(out)
f.close()

print out

args = [CC]
if len(sys.argv) > 2:
    args.extend(sys.argv[1:-1])
args.append(cfile)

os.spawnvpe(os.P_WAIT, CC, args, os.environ)

os.remove(cfile)