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+# -----------------------------------------------------------------------------
+# hedit.py
+#
+# Paring of Fortran H Edit descriptions (Contributed by Pearu Peterson)
+#
+# These tokens can't be easily tokenized because they are of the following
+# form:
+#
+# nHc1...cn
+#
+# where n is a positive integer and c1 ... cn are characters.
+#
+# This example shows how to modify the state of the lexer to parse
+# such tokens
+# -----------------------------------------------------------------------------
+
+tokens = (
+ 'H_EDIT_DESCRIPTOR',
+ )
+
+# Tokens
+t_ignore = " \t\n"
+
+def t_H_EDIT_DESCRIPTOR(t):
+ r"\d+H.*" # This grabs all of the remaining text
+ i = t.value.index('H')
+ n = eval(t.value[:i])
+
+ # Adjust the tokenizing position
+ t.lexer.lexpos -= len(t.value) - (i+1+n)
+
+ t.value = t.value[i+1:i+1+n]
+ return t
+
+def t_error(t):
+ print "Illegal character '%s'" % t.value[0]
+ t.skip(1)
+
+# Build the lexer
+import lex
+lex.lex()
+lex.runmain()
+
+