Mercurial > lbo > hg > pcombinators
changeset 45:2bce673577a2 draft
arith_test: More performance, 2. Push parsers upward!
| author | Lewin Bormann <lbo@spheniscida.de> |
|---|---|
| date | Thu, 23 May 2019 21:44:04 +0200 |
| parents | 990d234e1488 |
| children | d1c1e4b60e63 |
| files | pcombinators/arith_test.py |
| diffstat | 1 files changed, 5 insertions(+), 3 deletions(-) [+] |
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--- a/pcombinators/arith_test.py Thu May 23 21:40:34 2019 +0200 +++ b/pcombinators/arith_test.py Thu May 23 21:44:04 2019 +0200 @@ -10,6 +10,8 @@ from pcombinators.combinators import * from pcombinators.primitives import * +skip_whitespace = Skip(Whitespace()) + def Parens(): """Parentheses contain a term.""" return (Operator('(') + Term() + Operator(')')) >> (lambda l: l[1]) @@ -24,7 +26,7 @@ def Operator(set): """An operator or parenthesis.""" - return Last(Skip(Whitespace()) + OneOf(set)) + return OneOf(set) def operator_result_to_tuple(l): if len(l) == 1: @@ -45,7 +47,7 @@ def parse(self, st): # Try to parse an atom, a product operator, and another product. - p = OptimisticSequence(Power(), Operator('*/') + Product()) >> operator_result_to_tuple + p = OptimisticSequence(Power(), skip_whitespace, Operator('*/') + skip_whitespace + Product()) >> operator_result_to_tuple return p.parse(st) class Term(Parser): @@ -53,7 +55,7 @@ def parse(self, st): # Try to parse a product, then a sum operator, then another term. # OptimisticSequence will just return a product if there is no sum operator. - p = OptimisticSequence(Product(), Operator('+-') + Term()) >> operator_result_to_tuple + p = OptimisticSequence(Product(), skip_whitespace, Operator('+-') + skip_whitespace + Term()) >> operator_result_to_tuple return p.parse(st) def pretty_print(tpl):