add - to binary operators, do not space binary operators at start of string

zblz · zblz · commit debb5fcfac16 · 2015-09-03T15:52:12.000+01:00
diff --git a/lib/matplotlib/mathtext.py b/lib/matplotlib/mathtext.py
@@ -2083,7 +2083,7 @@ class Parser(object):
     corners.
     """
     _binary_operators = set('''
-      + *
+      + * -
       \\pm             \\sqcap                   \\rhd
       \\mp             \\sqcup                   \\unlhd
       \\times          \\vee                     \\unrhd
@@ -2499,10 +2499,22 @@ def symbol(self, s, loc, toks):
             raise ParseFatalException(s, loc, "Unknown symbol: %s" % c)
 
         if c in self._spaced_symbols:
-            return [Hlist( [self._make_space(0.2),
-                            char,
-                            self._make_space(0.2)] ,
-                           do_kern = True)]
+            # iterate until we find previous character, needed for cases
+            # such as ${ -2}$, $ -2$, or $   -2$.
+            i = 1
+            prev_char = s[loc-i]
+            while prev_char == ' ' and i <= loc:
+                i += 1
+                prev_char = s[loc-i]
+            # Binary operators at start of string should not be spaced
+            if (c in self._binary_operators and
+                    (len(s[:loc].split()) == 0 or prev_char == '{')):
+                return [char]
+            else:
+                return [Hlist( [self._make_space(0.2),
+                                char,
+                                self._make_space(0.2)] ,
+                               do_kern = True)]
         elif c in self._punctuation_symbols:
             return [Hlist( [char,
                             self._make_space(0.2)] ,
diff --git a/lib/matplotlib/tests/test_mathtext.py b/lib/matplotlib/tests/test_mathtext.py
@@ -102,7 +102,8 @@
     r'${xyz}^k{x}_{k}{x}^{p}{y}^{p-2} {d}_{i}^{j}{b}_{j}{c}_{k}{d} {x}^{j}_{i}{E}^{0}{E}^0_u$',
     r'${\int}_x^x x\oint_x^x x\int_{X}^{X}x\int_x x \int^x x \int_{x} x\int^{x}{\int}_{x} x{\int}^{x}_{x}x$',
     r'testing$^{123}$',
-    ' '.join('$\\' + p + '$' for p in sorted(mathtext.Parser._snowflake))
+    ' '.join('$\\' + p + '$' for p in sorted(mathtext.Parser._snowflake)),
+    r'$6-2$; $-2$; $ -2$; ${-2}$; ${  -2}$; $20^{+3}_{-2}$',
 ]
 
 digits = "0123456789"

Original file line number	Diff line number	Diff line change
`@@ -102,7 +102,8 @@`
`102`	`102`	`r'${xyz}^k{x}_{k}{x}^{p}{y}^{p-2} {d}_{i}^{j}{b}_{j}{c}_{k}{d} {x}^{j}_{i}{E}^{0}{E}^0_u$',`
`103`	`103`	`r'${\int}_x^x x\oint_x^x x\int_{X}^{X}x\int_x x \int^x x \int_{x} x\int^{x}{\int}_{x} x{\int}^{x}_{x}x$',`
`104`	`104`	`r'testing$^{123}$',`
`105`		`- ' '.join('$\\' + p + '$' for p in sorted(mathtext.Parser._snowflake))`
	`105`	`+ ' '.join('$\\' + p + '$' for p in sorted(mathtext.Parser._snowflake)),`
	`106`	`+ r'$6-2$; $-2$; $ -2$; ${-2}$; ${ -2}$; $20^{+3}_{-2}$',`
`106`	`107`	`]`
`107`	`108`
`108`	`109`	`digits = "0123456789"`