Script feature fix

doc/public/course_data_formats/symbolic_response.rst

@@ -19,8 +19,22 @@ This is a partial list of features, to be revised as we go along:
 
       An example of a problem::
 
-	  <symbolicresponse expect="a_b^c + b_x__d" size="30">
-            <textline math="1" preprocessorClassName="SymbolicMathjaxPreprocessor" preprocessorSrc="/static/js/capa/symbolic_mathjax_preprocessor.js"/>
-	  </symbolicresponse>
+      <symbolicresponse expect="a_b^c + b_x__d" size="30">
+        <textline math="1"
+           preprocessorClassName="SymbolicMathjaxPreprocessor"
+           preprocessorSrc="/static/js/capa/symbolic_mathjax_preprocessor.js"/>
+      </symbolicresponse>
 
       It's a bit of a pain to enter that.
+
+    * The script-style math variant. What would be outputted in latex if you
+      entered ``\mathcal{N}``. This is used in some variables.
+
+      An example::
+
+          <symbolicresponse expect="scriptN_B + x" size="30">
+            <textline math="1"/>
+          </symbolicresponse>
+
+      There is no fancy preprocessing needed, but if you had superscripts or
+      something, you would need to include that part.

lms/lib/symmath/formula.py

@@ -74,6 +74,15 @@ def to_latex(x):
     # LatexPrinter._print_dot = _print_dot
     xs = latex(x)
     xs = xs.replace(r'\XI', 'XI')	 # workaround for strange greek
+
+    # substitute back into latex form for scripts
+    # literally something of the form
+    # 'scriptN' becomes '\\mathcal{N}'
+    # note: can't use something akin to the _print_hat method above because we sometimes get 'script(N)__B' or more complicated terms
+    xs = re.sub(r'script([a-zA-Z0-9]+)',
+                '\\mathcal{\\1}',
+                xs)
+
     #return '<math>%s{}{}</math>' % (xs[1:-1])
     if xs[0] == '$':
         return '[mathjax]%s[/mathjax]<br>' % (xs[1:-1])	 # for sympy v6
@@ -106,6 +115,7 @@ def my_sympify(expr, normphase=False, matrix=False, abcsym=False, do_qubit=False
                   'i': sympy.I,			# lowercase i is also sqrt(-1)
                   'Q': sympy.Symbol('Q'),	 # otherwise it is a sympy "ask key"
                   'I': sympy.Symbol('I'),	 # otherwise it is sqrt(-1)
+                  'N': sympy.Symbol('N'),	 # or it is some kind of sympy function
                   #'X':sympy.sympify('Matrix([[0,1],[1,0]])'),
                   #'Y':sympy.sympify('Matrix([[0,-I],[I,0]])'),
                   #'Z':sympy.sympify('Matrix([[1,0],[0,-1]])'),
@@ -266,6 +276,21 @@ class formula(object):
             elif tag == 'mrow': return ''.join([flatten_pmathml(y) for y in xml])
             raise Exception, '[flatten_pmathml] unknown tag %s' % tag
 
+        def fix_mathvariant(parent):
+            '''Fix certain kinds of math variants
+
+            Literally replace <mstyle mathvariant="script"><mi>N</mi></mstyle>
+            with 'scriptN'. There have been problems using script_N or script(N)
+            '''
+            for child in parent:
+                if (gettag(child) == 'mstyle' and child.get('mathvariant') == 'script'):
+                    newchild = etree.Element('mi')
+                    newchild.text = 'script%s' % flatten_pmathml(child[0])
+                    parent.replace(child, newchild)
+                fix_mathvariant(child)
+        fix_mathvariant(xml)
+
+
         # find "tagged" superscripts
         # they have the character \u200b in the superscript
         # replace them with a__b so snuggle doesn't get confused

lms/lib/symmath/test_formula.py

+"""
+Tests of symbolic math
+"""
+
+
+import unittest
+import formula
+import re
+from lxml import etree
+
+def stripXML(xml):
+    xml = xml.replace('\n', '')
+    xml = re.sub(r'\> +\<', '><', xml)
+    return xml
+
+class FormulaTest(unittest.TestCase):
+    # for readability later
+    mathml_start = '<math xmlns="http://www.w3.org/1998/Math/MathML"><mstyle displaystyle="true">'
+    mathml_end = '</mstyle></math>'
+
+    def setUp(self):
+        self.formulaInstance = formula.formula('')
+
+    def test_replace_mathvariants(self):
+        expr = '''
+<mstyle mathvariant="script">
+  <mi>N</mi>
+</mstyle>'''
+
+        expected = '<mi>scriptN</mi>'
+
+        # wrap
+        expr = stripXML(self.mathml_start + expr + self.mathml_end)
+        expected = stripXML(self.mathml_start + expected + self.mathml_end)
+
+        # process the expression
+        xml = etree.fromstring(expr)
+        xml = self.formulaInstance.preprocess_pmathml(xml)
+        test = etree.tostring(xml)
+
+        # success?
+        self.assertEqual(test, expected)
+
+
+    def test_fix_simple_superscripts(self):
+        expr = '''
+<msup>
+  <mi>a</mi>
+  <mrow>
+    <mo>&#x200B;</mo>
+    <mi>b</mi>
+  </mrow>
+</msup>'''
+
+        expected = '<mi>a__b</mi>'
+
+        # wrap
+        expr = stripXML(self.mathml_start + expr + self.mathml_end)
+        expected = stripXML(self.mathml_start + expected + self.mathml_end)
+
+        # process the expression
+        xml = etree.fromstring(expr)
+        xml = self.formulaInstance.preprocess_pmathml(xml)
+        test = etree.tostring(xml)
+
+        # success?
+        self.assertEqual(test, expected)
+
+    def test_fix_complex_superscripts(self):
+        expr = '''
+<msubsup>
+  <mi>a</mi>
+  <mi>b</mi>
+  <mrow>
+    <mo>&#x200B;</mo>
+    <mi>c</mi>
+  </mrow>
+</msubsup>'''
+
+        expected = '<mi>a_b__c</mi>'
+
+        # wrap
+        expr = stripXML(self.mathml_start + expr + self.mathml_end)
+        expected = stripXML(self.mathml_start + expected + self.mathml_end)
+
+        # process the expression
+        xml = etree.fromstring(expr)
+        xml = self.formulaInstance.preprocess_pmathml(xml)
+        test = etree.tostring(xml)
+
+        # success?
+        self.assertEqual(test, expected)
+
+
+    def test_fix_msubsup(self):
+        expr = '''
+<msubsup>
+  <mi>a</mi>
+  <mi>b</mi>
+  <mi>c</mi>
+</msubsup>'''
+
+        expected = '<msup><mi>a_b</mi><mi>c</mi></msup>' # which is (a_b)^c
+
+        # wrap
+        expr = stripXML(self.mathml_start + expr + self.mathml_end)
+        expected = stripXML(self.mathml_start + expected + self.mathml_end)
+
+        # process the expression
+        xml = etree.fromstring(expr)
+        xml = self.formulaInstance.preprocess_pmathml(xml)
+        test = etree.tostring(xml)
+
+        # success?
+        self.assertEqual(test, expected)