#!/usr/bin/env python
"""
Preparse a .sage file and save the result to a .py file.
AUTHOR:
-- William Stein (2005): first version
-- William Stein (2008): fix trac #2391 and document the code.
-- Dan Drake (2009): fix trac #5052
-- Dan Drake (2010-12-08): fix trac #10440
"""
import os, sys, re
# The spkg/bin/sage script passes the files to be preparsed as
# arguments (but remove sys.argv[0]).
files = sys.argv[1:]
# There must be at least 1 file or we display an error/usage message
# and exit
if len(files) == 0:
print "Usage: %s <file1.sage> <file2.sage>..."%sys.argv[0]
print "Creates files file1.py, file2.py ... that are the Sage"
print "preparsed versions of file1.sage, file2.sage ..."
print "If a non-autogenerated .py file with the same name"
print "exists, you will receive an error and the file will"
print "not be overwritten."
sys.exit(1)
# The module-scope variable contains a list of all files we
# have seen while preparsing a given file. The point of this
# is that we want to avoid preparsing a file we have already
# seen, since then infinite loops would result from mutual
# recursive includes.
files_so_far = []
# This message is inserted in autogenerated files so that the reader
# will know, and so we know it is safe to overwrite them.
AUTOGEN_MSG = "# This file was *autogenerated* from the file "
# We use this regexp to parse lines with load or attach statements.
# Here's what it looks for:
#
# A (possibly empty) sequence of whitespace at the beginning of the
# line, saved as a group named 'lws';
#
# followed by
#
# the word "load" or "attach";
#
# followed by
#
# a nonempty sequence of whitespace;
#
# followed by
#
# whatever else is on the line, saved as a group named 'files'.
#
# We want to save the leading white space so that we can maintain
# correct indentation in the preparsed file.
load_or_attach = re.compile(r"^(?P<lws>\s*)(load|attach)\s+(?P<files>.*)$")
def do_preparse(f, files_before=[]):
"""
Preparse the file f and write the result out to a filename
with extension .py.
INPUT:
f -- string: the name of a file
files_before -- list of strings of previous filenames loaded (to avoid circular loops)
OUTPUT:
writes a file with extension .py to disk.
"""
if f in files_so_far:
return
files_so_far.append(f)
if not os.path.exists(f):
print "%s: File '%s' is missing"%(sys.argv[0], f)
return
if f[-3:] == '.py':
return
if f[-5:] != '.sage':
print "%s: Unknown file type %s"%(sys.argv[0], f)
sys.exit(1)
fname = '%s.py'%f[:-5]
if os.path.exists(fname):
if AUTOGEN_MSG not in open(fname).read():
print "Refusing to overwrite existing non-autogenerated file '%s'."%os.path.abspath(fname)
print "Please delete or move this .py file manually."
sys.exit(1)
# TODO:
# I am commenting this "intelligence" out, since, e.g., if I change
# the preparser between versions this can cause problems. This
# is an optimization that definitely isn't needed at present, since
# preparsing is so fast.
# Idea: I could introduce version numbers, though....
#if os.path.exists(fname) and os.path.getmtime(fname) >= os.path.getmtime(f):
# return
# Finally open the file
F = open(f).read()
# Check to see if a coding is specified in the .sage file. If it is,
# then we want to copy it over to the new file and not include it in
# the preprocessing. If both the first and second line have an
# encoding declaration, the second line's encoding will get used.
lines = F.splitlines()
coding = ''
for num, line in enumerate(lines[:2]):
if re.search(r"coding[:=]\s*([-\w.]+)", line):
coding = line + '\n'
F = '\n'.join(lines[:num] + lines[(num+1):])
# Preparse it
from sage.misc.preparser import preparse_file
G = preparse_file(F)
# Check for load/attach commands.
G = do_load_and_attach(G, f, files_before)
# Put the Sage library include along with a autogen message in the file.
# It is ** critical ** that we put this after the mdoule docstring, since
# otherwise the module docstring will disappear.
insert = '%s%s.\nfrom sage.all_cmdline import * # import sage library\n'%(AUTOGEN_MSG, f)
i = find_position_right_after_module_docstring(G)
G = coding + G[:i] + insert + G[i:]
# Finally, write out the result.
open(fname, 'w').write(G)
def find_position_right_after_module_docstring(G):
"""
Return first position right after the module docstring of G, if it
has one. Otherwise return 0.
INPUT:
G -- a string
OUTPUT:
an integer -- the index into G so that G[i] is right after
the module docstring of G, if G has one.
"""
# The basic idea below is that we look at each line first ignoring
# all empty lines and commented out lines. Then we check to see
# if the next line is a docstring. If so, we find where that
# docstring ends.
v = G.splitlines()
i = 0
while i < len(v):
s = v[i].strip()
if len(s) > 0 and s[0] != '#':
break
i += 1
if i >= len(v):
# No module docstring --- entire file is commented out
return 0
# Now v[i] contains the first line of the first statement in the file.
# Is it a docstring?
n = v[i].lstrip()
if not (n[0] in ['"',"'"] or n[0:2] in ['r"',"r'"]):
# not a docstring
return 0
# First line is the module docstring. Where does it end?
def pos_after_line(k):
return sum(len(v[j])+1 for j in range(k+1))
n = n.lstrip('r') # strip leading r if there is one
if n[:3] in ["'''", '"""']:
quotes = n[:3]
# possibly multiline
if quotes in n[3:]:
return pos_after_line(i)
j = i+1
while j < len(v) and quotes not in v[j]:
j += 1
return pos_after_line(j)
else:
# it must be a single line; so add up the lengths of all lines
# including this one and return that
return pos_after_line(i)
def do_load_and_attach(G, file, files_before):
"""
Parse a file G and replace load and attach statements with the
corresponding execfile() statements.
INPUT:
G -- a string; a file loaded in from disk
file -- the name of the file that contains the non-preparsed
version of G.
files_before -- list of files seen so far (don't recurse into
infinite loop)
OUTPUT:
string -- result of parsing load/attach statements in G, i.e.
modified version of G with execfiles.
"""
s = ''
for t in G.split('\n'):
z = load_or_attach.match(t)
if z:
files = z.group('files').split()
lws = z.group('lws')
for w in files:
name = w.replace(',','').replace('"','').replace("'","")
#print "'%s'"%name, files_before
if name in files_before:
print "WARNING: not loading %s (in %s) again since would cause circular loop"%(name, file)
continue
if name.endswith('.sage'):
do_preparse(name, files_before + [file])
s += lws + 'execfile("%s.py")\n'%name[:-5]
elif name.endswith('.py'):
s += lws + 'execfile("%s")\n'%name
else:
s += t + '\n'
return s
# Here we do the actual work. We iterate over ever
# file in the input args and create the corresponding
# output file.
for f in files:
do_preparse(f)
