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| author | Araq <rumpf_a@web.de> | 2011-11-09 01:42:05 +0100 |
|---|---|---|
| committer | Araq <rumpf_a@web.de> | 2011-11-09 01:42:05 +0100 |
| commit | 68be801f63dc41e79f96ef2516350cc8538c5d7e (patch) | |
| tree | 79e30a2a6024daff3602099ac403bdc68eb8d385 /doc | |
| parent | 8c03d96c6aaa9607d3cba4e1dab401b6e0a85890 (diff) | |
| download | Nim-68be801f63dc41e79f96ef2516350cc8538c5d7e.tar.gz | |
operator precedence changed: assignment like operators are supported; escaping of operators with \ is supported
Diffstat (limited to 'doc')
| -rwxr-xr-x | doc/grammar.txt | 5 | ||||
| -rwxr-xr-x | doc/manual.txt | 25 |
2 files changed, 22 insertions, 8 deletions
diff --git a/doc/grammar.txt b/doc/grammar.txt index 458c85833..5f7b851fa 100755 --- a/doc/grammar.txt +++ b/doc/grammar.txt @@ -1,7 +1,7 @@ module ::= ([COMMENT] [SAD] stmt)* comma ::= ',' [COMMENT] [IND] -operator ::= OP1 | OP2 | OP3 | OP4 | OP5 | OP6 | OP7 | OP8 | OP9 +operator ::= OP0 | OP1 | OP2 | OP3 | OP4 | OP5 | OP6 | OP7 | OP8 | OP9 | 'or' | 'xor' | 'and' | 'is' | 'isnot' | 'in' | 'notin' | 'of' | 'div' | 'mod' | 'shl' | 'shr' | 'not' | '..' @@ -11,7 +11,8 @@ prefixOperator ::= operator optInd ::= [COMMENT] [IND] optPar ::= [IND] | [SAD] -lowestExpr ::= orExpr (OP1 optInd orExpr)* +lowestExpr ::= assignExpr (OP0 optInd assignExpr)* +assignExpr ::= orExpr (OP1 optInd orExpr)* orExpr ::= andExpr (OP2 optInd andExpr)* andExpr ::= cmpExpr (OP3 optInd cmpExpr)* cmpExpr ::= sliceExpr (OP4 optInd sliceExpr)* diff --git a/doc/manual.txt b/doc/manual.txt index 44bd99352..6d8286dd7 100755 --- a/doc/manual.txt +++ b/doc/manual.txt @@ -387,13 +387,25 @@ This section lists Nimrod's standard syntax in ENBF. How the parser receives indentation tokens is already described in the `Lexical Analysis`_ section. Nimrod allows user-definable operators. -Binary operators have 9 different levels of precedence. For user-defined -operators, the precedence depends on the first character the operator consists -of. All binary operators are left-associative, except binary operators starting -with (or only consisting of) ``^``. +Binary operators have 10 different levels of precedence. +All binary operators are left-associative, except binary operators starting +with (or only consisting of) ``^``. + +For operators that are not keywords the precedence is determined by the +following rules: + +An operator symbol's *relevant character* is its first +character unless the first character is ``\`` and its length is greater than 1 +then it is the second character. + +If the operator ends with ``=`` and its relevant character is none of +``<``, ``>``, ``!``, ``=``, ``~``, ``?``, it is an *assignment operator* which +has the lowest precedence. + +Otherwise precedence is determined by the relevant character. ================ =============================================== ================== =============== -Precedence level Operators First characters Terminal symbol +Precedence level Operators Relevant character Terminal symbol ================ =============================================== ================== =============== 9 (highest) ``$ ^`` OP9 8 ``* / div mod shl shr %`` ``* % \ /`` OP8 @@ -403,7 +415,8 @@ Precedence level Operators First charact 4 ``== <= < >= > != in not_in is isnot not of`` ``= < > !`` OP4 3 ``and`` OP3 2 ``or xor`` OP2 - 1 (lowest) ``@ : ?`` OP1 + 1 ``@ : ?`` OP1 + 0 (lowest) *assignment operator* (like ``+=``, ``*=``) OP0 ================ =============================================== ================== =============== |