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Commit 28a1ca8a by Peter Baratta
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Comment fixes

parent af1f8c1f
Showing with 37 additions and 22 deletions
common/lib/calc/preview.py
......@@ -5,7 +5,7 @@ That is, given a math string, parse it and render each branch of the result,
always returning valid latex.
Because intermediate values of the render contain more data than simply the
string of latex, store it in a custom class `LatexRendered`
string of latex, store it in a custom class `LatexRendered`.
"""
from calc import ParseAugmenter, add_defaults, SUFFIXES
......@@ -16,26 +16,26 @@ class LatexRendered(object):
Data structure to hold a typeset representation of some math.
Fields:
-`latex` is a generated, valid latex string (as if it were standalone)
-`sans_parens` is usually the same as `latex` except without the outermost
parens (if applicable)
-`tall` is a boolean representing if the latex has any elements extending
above or below a normal height, specifically things of the form 'a^b' and
'\frac{a}{b}'. This affects the height of wrapping parenthesis.
-`latex` is a generated, valid latex string (as if it were standalone).
-`sans_parens` is usually the same as `latex` except without the outermost
parens (if applicable).
-`tall` is a boolean representing if the latex has any elements extending
above or below a normal height, specifically things of the form 'a^b' and
'\frac{a}{b}'. This affects the height of wrapping parenthesis.
"""
def __init__(self, latex, parens=None, tall=False):
"""
Instantiate with the latex representing the math
Instantiate with the latex representing the math.
Optionally include parenthesis to wrap around it and the height.
`parens` must be one of '(', '[' or '{'
`tall` is a boolean (see note above)
`parens` must be one of '(', '[' or '{'.
`tall` is a boolean (see note above).
"""
self.latex = latex
self.sans_parens = latex
self.tall = tall
# generate parens and overwrite self.latex
# Generate parens and overwrite `self.latex`.
if parens is not None:
left_parens = parens
if left_parens == '{':
......@@ -107,6 +107,7 @@ def function_closure(functions, casify):
if casify(fname) not in functions:
pass
# Wrap the input of the function with parens or braces.
inner = children[1].latex
if fname == "sqrt":
inner = u"{{{expr}}}".format(expr=inner)
......@@ -116,6 +117,7 @@ def function_closure(functions, casify):
else:
inner = u"({expr})".format(expr=inner)
# Correctly format the name of the function.
if fname == "sqrt":
fname = ur"\sqrt"
elif fname == "log10":
......@@ -125,8 +127,10 @@ def function_closure(functions, casify):
else:
fname = ur"\text{{{fname}}}".format(fname=fname)
# Put it together.
latex = fname + inner
return LatexRendered(latex, tall=children[1].tall)
# Return the function within the closure.
return render_function
......@@ -134,7 +138,8 @@ def render_power(children):
"""
Combine powers so that the latex is wrapped in curly braces correctly.
If you have 'a^(b+c)' don't include that last set of parens ('a^{b+c}').
Also, if you have 'a^(b+c)' don't include that last set of parens:
'a^{b+c}' is correct, whereas 'a^{(b+c)}' is extraneous.
"""
if len(children) == 1:
return children[0]
......@@ -149,7 +154,7 @@ def render_power(children):
def render_parallel(children):
"""
Simply combine elements with a double vertical line.
Simply join the child nodes with a double vertical line.
"""
children_latex = [k.latex for k in children if k.latex != "||"]
latex = r"\|".join(children_latex)
......@@ -161,7 +166,7 @@ def render_frac(numerator, denominator):
r"""
Given a list of elements in the numerator and denominator, return a '\frac'
Avoid parens if there is only thing in that part
Avoid parens if they are unnecessary (i.e. the only thing in that part).
"""
if len(numerator) == 1:
num_latex = numerator[0].sans_parens
......@@ -181,9 +186,15 @@ def render_product(children):
r"""
Format products and division nicely.
That is, group bunches of adjacent, equal operators. For every time it
switches from numerator to denominator, call `render_frac`. Join these
groupings by '\cdot's.
Group bunches of adjacent, equal operators. Every time it switches from
denominator to the next numerator, call `render_frac`. Join these groupings
together with '\cdot's, ending on a numerator if needed.
Examples: (`children` is formed indirectly by the string on the left)
'a*b' -> 'a\cdot b'
'a/b' -> '\frac{a}{b}'
'a*b/c/d' -> '\frac{a\cdot b}{c\cdot d}'
'a/b*c/d*e' -> '\frac{a}{b}\cdot \frac{c}{d}\cdot e'
"""
position = "numerator" # or denominator
fraction_mode_ever = False
......@@ -194,29 +205,33 @@ def render_product(children):
for kid in children:
if position == "numerator":
if kid.latex == "*":
pass
pass # Don't explicitly add the '\cdot' yet.
elif kid.latex == "/":
# Switch to denominator mode.
fraction_mode_ever = True
position = "denominator"
else:
numerator.append(kid)
else:
if kid.latex == "*":
# render the current fraction and add it to the latex
# Switch back to numerator mode.
# First, render the current fraction and add it to the latex.
latex += render_frac(numerator, denominator) + r"\cdot "
# reset back to beginning state
# Reset back to beginning state
position = "numerator"
numerator = []
denominator = []
elif kid.latex == "/":
pass
pass # Don't explicitly add a '\frac' yet.
else:
denominator.append(kid)
# Add the fraction/numerator that we ended on.
if position == "denominator":
latex += render_frac(numerator, denominator)
else:
# We ended on a numerator--act like normal multiplication.
num_latex = r"\cdot ".join(k.latex for k in numerator)
latex += num_latex
......@@ -226,7 +241,7 @@ def render_product(children):
def render_sum(children):
"""
Combine elements, including their operators.
Concatenate elements, including the operators.
"""
children_latex = [k.latex for k in children]
latex = "".join(children_latex)
......
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