1 "{ Package: 'squeak:petitparser' }"

     2 

     3 PPCompositeParser subclass:#PPArithmeticParser

     4 	instanceVariableNames:'terms addition factors multiplication power primary parentheses

     5 		number'

     6 	classVariableNames:''

     7 	poolDictionaries:''

     8 	category:'PetitTests-Examples'

     9 !

    10 

    11 

    12 !PPArithmeticParser methodsFor:'accessing'!

    13 

    14 start

    15 	^ terms end

    16 ! !

    17 

    18 !PPArithmeticParser methodsFor:'grammar'!

    19 

    20 addition

    21 	^ (factors separatedBy: ($+ asParser / $- asParser) token trim) 

    22 		foldLeft: [ :a :op :b | a perform: op value asSymbol with: b ]

    23 !

    24 

    25 factors

    26 	^ multiplication / power

    27 !

    28 

    29 multiplication

    30 	^ (power separatedBy: ($* asParser / $/ asParser) token trim)

    31 		foldLeft: [ :a :op :b | a perform: op value asSymbol with: b ]

    32 !

    33 

    34 number

    35 	^ ($- asParser optional , #digit asParser plus , ($. asParser , #digit asParser plus) optional) token trim ==> [ :token | token value asNumber ]

    36 !

    37 

    38 parentheses

    39 	^ $( asParser flatten trim , terms , $) asParser flatten trim ==> #second

    40 !

    41 

    42 power

    43 	^ (primary separatedBy: $^ asParser token trim) foldRight: [ :a :op :b | a raisedTo: b ]

    44 !

    45 

    46 primary

    47 	^ number / parentheses

    48 !

    49 

    50 terms

    51 	^ addition / factors

    52 ! !

    53 

    54 !PPArithmeticParser class methodsFor:'documentation'!

    55 

    56 version_SVN

    57     ^ '$Id: PPArithmeticParser.st,v 1.1 2011-08-18 18:56:17 cg Exp $'

    58 ! !