66 lines
1.4 KiB
Smalltalk
66 lines
1.4 KiB
Smalltalk
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Class {
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#name : 'PPArithmeticParser',
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#superclass : 'PPCompositeParser',
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#instVars : [
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'terms',
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'addition',
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'factors',
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'multiplication',
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'power',
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'primary',
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'parentheses',
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'number'
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],
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#category : 'PetitTests-Examples'
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}
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{ #category : 'grammar' }
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PPArithmeticParser >> addition [
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^ (factors separatedBy: ($+ asParser / $- asParser) trim)
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foldLeft: [ :a :op :b | a perform: op asSymbol with: b ]
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]
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{ #category : 'grammar' }
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PPArithmeticParser >> factors [
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^ multiplication / power
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]
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{ #category : 'grammar' }
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PPArithmeticParser >> multiplication [
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^ (power separatedBy: ($* asParser / $/ asParser) trim)
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foldLeft: [ :a :op :b | a perform: op asSymbol with: b ]
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]
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{ #category : 'grammar' }
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PPArithmeticParser >> number [
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^ ($- asParser optional , #digit asParser plus , ($. asParser , #digit asParser plus) optional) flatten trim
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==> [ :value | value asNumber ]
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]
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{ #category : 'grammar' }
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PPArithmeticParser >> parentheses [
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^ $( asParser trim , terms , $) asParser trim
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==> [ :nodes | nodes at: 2 ]
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]
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{ #category : 'grammar' }
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PPArithmeticParser >> power [
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^ (primary separatedBy: $^ asParser trim)
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foldRight: [ :a :op :b | a raisedTo: b ]
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]
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{ #category : 'grammar' }
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PPArithmeticParser >> primary [
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^ number / parentheses
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]
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{ #category : 'accessing' }
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PPArithmeticParser >> start [
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^ terms end
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]
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{ #category : 'grammar' }
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PPArithmeticParser >> terms [
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^ addition / factors
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]
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