Adding script to generate latex_symbols.py.

tools/gen_latex_symbols.py

@@ -0,0 +1,76 b''
+# coding: utf-8
+
+# This script autogenerates `IPython.core.latex_symbols.py`, which contains a
+# single dict , named `latex_symbols`. The keys in this dict are latex symbols,
+# such as `\\alpha` and the values in the dict are the unicode equivalents for
+# those. Most importantly, only unicode symbols that are valid identifers in
+# Python 3 are included. 
+
+# 
+# The original mapping of latex symbols to unicode comes from the `latex_symbols.jl` files from Julia.
+
+from __future__ import print_function
+
+# Import the Julia LaTeX symbols
+print('Importing latex_symbols.js from Julia...')
+import requests
+url = 'https://raw.githubusercontent.com/JuliaLang/julia/master/base/latex_symbols.jl'
+r = requests.get(url)
+
+
+# Build a list of key, value pairs
+print('Building a list of (latex, unicode) key-vaule pairs...')
+lines = r.text.splitlines()[60:]
+lines = [line for line in lines if '=>' in line]
+lines = [line.replace('=>',':') for line in lines]
+
+def line_to_tuple(line):
+    """Convert a single line of the .jl file to a 2-tuple of strings like ("\\alpha", "α")"""
+    kv = line.split(',')[0].split(':')
+#     kv = tuple(line.strip(', ').split(':'))
+    k, v = kv[0].strip(' "'), kv[1].strip(' "')
+#     if not test_ident(v):
+#         print(line)
+    return k, v
+
+assert line_to_tuple('    "\\sqrt" : "\u221A",') == ('\\sqrt', '\u221A')
+lines = [line_to_tuple(line) for line in lines]
+
+
+# Filter out non-valid identifiers
+print('Filtering out characters that are not valid Python 3 identifiers')
+
+def test_ident(i):
+    """Is the unicode string a valid Python 3 identifer."""
+    try:
+        exec('a%s = 10' % i, {}, {})
+    except SyntaxError:
+        return False
+    else:
+        return True
+
+assert test_ident("α")
+assert not test_ident('‴')
+
+valid_idents = [line for line in lines if test_ident(line[1])]
+
+
+# Write the `latex_symbols.py` module in the cwd
+
+s = """# encoding: utf-8
+
+# This file is autogenerated from the file:
+# https://raw.githubusercontent.com/JuliaLang/julia/master/base/latex_symbols.jl
+# This original list is filtered to remove any unicode characters that are not valid
+# Python identifiers.
+
+latex_symbols = {\n
+"""
+for line in valid_idents:
+    s += '    "%s" : "%s",\n' % (line[0], line[1])
+s += "}\n"
+
+with open('latex_symbols.py', 'w', encoding='utf-8') as f:
+    f.write(s)
+
+