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compiler\parser.nim

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implemented arrow like operators
This commit is contained in:
Araq 2014-12-08 08:56:04 +01:00
commit 2804c0373c
2 changed files with 36 additions and 37 deletions
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23
doc/grammar.txt
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@ -4,7 +4,7 @@ semicolon = ';' COMMENT?
colon = ':' COMMENT? colon = ':' COMMENT?
colcom = ':' COMMENT? colcom = ':' COMMENT?
operator = OP0 | OP1 | OP2 | OP3 | OP4 | OP5 | OP6 | OP7 | OP8 | OP9 operator = OP0 | OP1 | OP2 | OP3 | OP4 | OP5 | OP6 | OP7 | OP8 | OP9 | OP10
| 'or' | 'xor' | 'and' | 'or' | 'xor' | 'and'
| 'is' | 'isnot' | 'in' | 'notin' | 'of' | 'is' | 'isnot' | 'in' | 'notin' | 'of'
| 'div' | 'mod' | 'shl' | 'shr' | 'not' | 'addr' | 'static' | '..' | 'div' | 'mod' | 'shl' | 'shr' | 'not' | 'addr' | 'static' | '..'
@ -14,16 +14,17 @@ prefixOperator = operator
optInd = COMMENT? optInd = COMMENT?
optPar = (IND{>} | IND{=})? optPar = (IND{>} | IND{=})?
simpleExpr = assignExpr (OP0 optInd assignExpr)* simpleExpr = arrowExpr (OP0 optInd arrowExpr)*
assignExpr = orExpr (OP1 optInd orExpr)* arrowExpr = assignExpr (OP1 optInd assignExpr)*
orExpr = andExpr (OP2 optInd andExpr)* assignExpr = orExpr (OP2 optInd orExpr)*
andExpr = cmpExpr (OP3 optInd cmpExpr)* orExpr = andExpr (OP3 optInd andExpr)*
cmpExpr = sliceExpr (OP4 optInd sliceExpr)* andExpr = cmpExpr (OP4 optInd cmpExpr)*
sliceExpr = ampExpr (OP5 optInd ampExpr)* cmpExpr = sliceExpr (OP5 optInd sliceExpr)*
ampExpr = plusExpr (OP6 optInd plusExpr)* sliceExpr = ampExpr (OP6 optInd ampExpr)*
plusExpr = mulExpr (OP7 optInd mulExpr)* ampExpr = plusExpr (OP7 optInd plusExpr)*
mulExpr = dollarExpr (OP8 optInd dollarExpr)* plusExpr = mulExpr (OP8 optInd mulExpr)*
dollarExpr = primary (OP9 optInd primary)* mulExpr = dollarExpr (OP9 optInd dollarExpr)*
dollarExpr = primary (OP10 optInd primary)*
symbol = '`' (KEYW|IDENT|literal|(operator|'('|')'|'['|']'|'{'|'}'|'=')+)+ '`' symbol = '`' (KEYW|IDENT|literal|(operator|'('|')'|'['|']'|'{'|'}'|'=')+)+ '`'
| IDENT | IDENT
indexExpr = expr indexExpr = expr

50
doc/manual/syntax.txt
View file

@ -5,24 +5,21 @@ This section lists Nim's standard syntax. How the parser handles
the indentation is already described in the `Lexical Analysis`_ section. the indentation is already described in the `Lexical Analysis`_ section.
Nim allows user-definable operators. Nim allows user-definable operators.
Binary operators have 10 different levels of precedence. Binary operators have 11 different levels of precedence.
Relevant character
------------------
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.
This rule allows to escape operator symbols with ``\`` and keeps the operator's
precedence and associativity; this is useful for meta programming.
Associativity Associativity
------------- -------------
Binary operators whose relevant character is ``^`` are right-associative, all Binary operators whose first character is ``^`` or its last character
other binary operators are left-associative. is ``>`` are right-associative, all other binary operators are left-associative.
Exception: The single "greater than" ``>`` operator is left-associative too.
Operators ending in ``>`` but longer than a single character are
called `arrow like`:idx:.
Precedence Precedence
---------- ----------
@ -30,7 +27,7 @@ Precedence
Unary operators always bind stronger than any binary Unary operators always bind stronger than any binary
operator: ``$a + b`` is ``($a) + b`` and not ``$(a + b)``. operator: ``$a + b`` is ``($a) + b`` and not ``$(a + b)``.
If an unary operator's relevant character is ``@`` it is a `sigil-like`:idx: If an unary operator's first character is ``@`` it is a `sigil-like`:idx:
operator which binds stronger than a ``primarySuffix``: ``@x.abc`` is parsed operator which binds stronger than a ``primarySuffix``: ``@x.abc`` is parsed
as ``(@x).abc`` whereas ``$x.abc`` is parsed as ``$(x.abc)``. as ``(@x).abc`` whereas ``$x.abc`` is parsed as ``$(x.abc)``.
@ -38,25 +35,26 @@ as ``(@x).abc`` whereas ``$x.abc`` is parsed as ``$(x.abc)``.
For binary operators that are not keywords the precedence is determined by the For binary operators that are not keywords the precedence is determined by the
following rules: following rules:
If the operator ends with ``=`` and its relevant character is none of If the operator ends with ``=`` and its first character is none of
``<``, ``>``, ``!``, ``=``, ``~``, ``?``, it is an *assignment operator* which ``<``, ``>``, ``!``, ``=``, ``~``, ``?``, it is an *assignment operator* which
has the lowest precedence. has the lowest precedence.
Otherwise precedence is determined by the relevant character. Otherwise precedence is determined by the first character.
================ =============================================== ================== =============== ================ =============================================== ================== ===============
Precedence level Operators Relevant character Terminal symbol Precedence level Operators First character Terminal symbol
================ =============================================== ================== =============== ================ =============================================== ================== ===============
9 (highest) ``$ ^`` OP9 10 (highest) ``$ ^`` OP10
8 ``* / div mod shl shr %`` ``* % \ /`` OP8 9 ``* / div mod shl shr %`` ``* % \ /`` OP9
7 ``+ -`` ``+ ~ |`` OP7 8 ``+ -`` ``+ ~ |`` OP8
6 ``&`` ``&`` OP6 7 ``&`` ``&`` OP7
5 ``..`` ``.`` OP5 6 ``..`` ``.`` OP6
4 ``== <= < >= > != in notin is isnot not of`` ``= < > !`` OP4 5 ``== <= < >= > != in notin is isnot not of`` ``= < > !`` OP5
3 ``and`` OP3 4 ``and`` OP4
2 ``or xor`` OP2 3 ``or xor`` OP3
1 ``@ : ?`` OP1 2 ``@ : ?`` OP2
0 (lowest) *assignment operator* (like ``+=``, ``*=``) OP0 1 *assignment operator* (like ``+=``, ``*=``) OP1
0 (lowest) *arrow like operator* (like ``->``, ``=>``) OP0
================ =============================================== ================== =============== ================ =============================================== ================== ===============