AntonAntonov/FunctionalParsers

Food cravings grammar and interpreters

Introduction	Random sentences generation
Grammar	Interpreters

Introduction

In this notebook we show how to make a grammar for a simple Domain Specific Language (DSL) that has sentences proclaiming food cravings and affinities.

Load the paclet

In[11]:=

Needs["AntonAntonov`FunctionalParsers`"]

Grammar

Here is an EBNF description of a Domain Specific Language (DSL) for food cravings:

In[12]:=

ebnfCode=" <lovefood> = <subject> , <loveverb> , <object-spec> <@ LoveFood[Flatten[#]]& ; <loveverb> = ( 'love' | 'crave' | 'demand' ) <@ LoveType ; <object-spec> = ( <object-list> | <object> | <objects> | <objects-mult> ) <@ LoveObjects[Flatten[{#}]]& ; <subject> = 'i' | 'we' | 'you' <@ Who ; <object> = 'sushi' | [ 'a' ] , 'chocolate' | 'milk' | [ 'an' , 'ice' ] , 'cream' | 'a' , 'tangerine' ; <objects> = 'sushi' | 'chocolates' | 'milks' | 'ice' , 'creams' | 'ice-creams' | 'tangerines' ; <objects-mult> = 'Range[2,100]' , <objects> <@ Mult ; <object-list> = ( <object> | <objects> | <objects-mult> ) , { 'and' &> ( <object> | <objects> | <objects-mult> ) } ; ";

Generate parsers from the EBNF string:

In[13]:=

GenerateParsersFromEBNF



ParseToTokens

@ebnfCode;

Test the parser

pLOVEFOOD

-- for the highest level rule "<lovefood>" -- with a list of sentences:

In[14]:=

sentences={"I love milk","We demand 2 ice creams","I crave 2 ice creams and 5 chocolates","You crave chocolate and milk"};

ParsingTestTable

[pLOVEFOOD,ToLowerCase@sentences,"Layout""Vertical"]

Out[14]=

1	command:	i love milk
	parsed:	LoveFood[{Who[i],LoveType[love],LoveObjects[{milk}]}]
	residual:	{}
2	command:	we demand 2 ice creams
	parsed:	LoveFood[{Who[we],LoveType[demand],LoveObjects[{Mult[{2,{ice,creams}}]}]}]
	residual:	{}
3	command:	i crave 2 ice creams and 5 chocolates
	parsed:	LoveFood[{Who[i],LoveType[crave],LoveObjects[{Mult[{2,{ice,creams}}],Mult[{5,chocolates}]}]}]
	residual:	{}
4	command:	you crave chocolate and milk
	parsed:	LoveFood[{Who[you],LoveType[crave],LoveObjects[{chocolate,milk}]}]
	residual:	{}

Note the EBNF rule wrappers -- those are symbols specified at the ends of some of the rules.

Random sentences generation

Generate random sentences from the grammar above:

In[15]:=

SeedRandom[3];

GrammarRandomSentences



GrammarNormalize

[ebnfCode],12//Sort//ColumnForm

Out[16]=

i crave 59 milks

i demand 73 sushi and 43 tangerines and 77 ice creams and ice creams and 32 sushi and tangerines

i demand sushi

we crave ice-creams and 53 sushi and milk and 9 milks and sushi

we demand chocolates

we demand milks and 65 ice-creams and ice-creams

we love 14 ice-creams and tangerines and 47 milks

we love ice creams

we love milks and 31 ice creams and milks and cream

you demand milks

you love milk and 32 milks and a tangerine

you love tangerines

Interpreters

We can implement interpreters that tell calorie intake for proclaimed food affinities and cravings. We can use

WolframAlpha

to get the calories, but since using

WolframAlpha

can be slow it is overridden inside

Block

Interpreter for

LoveObjects

In[17]:=

Clear[LoveObjectsCalories];LoveObjectsCalories[parsed_]:=Block[{res,wares,WolframAlpha={}&},res=(StringJoin@@Flatten[Riffle[parsed," and "]/.Mult[{x_,y_}](StringJoin@@Riffle[Flatten[{ToString[x],y}]," "])]);wares=WolframAlpha[res<>" calories","DataRules",TimeConstraint60];{{"Result",1},"ComputableData"}/.wares/.{{"Result",1},"ComputableData"}Quantity[RandomInteger[{20,1200}],"LargeCalories"]];

Interpreter for

LoveFood

In[18]:=

Clear[LoveFoodCalories];LoveFoodCalories[parsed_]:=Block[{who,type},who=Cases[parsed,Who[id_]id,∞]〚1〛;type=Cases[parsed,LoveType[id_]id,∞]〚1〛;Which[who"you",Row[{"No, I do not. I am a machine."}],type"love",Row[{"you gain ",Sqrt[1*10.]parsed〚-1〛," per day"}],True,Row[{"you will gain ",parsed〚-1〛}]]];

Here the parsing tests are re-done by changing the definitions of the wrapping symbols

LoveFood

and

LoveObjects

In[20]:=

Block{LoveFood=LoveFoodCalories,LoveObjects=LoveObjectsCalories},

ParsingTestTable

[pLOVEFOOD,ToLowerCase@sentences,"Layout""Vertical"]

Out[20]=

1	command:	i love milk
	parsed:	you gain 3469.02 Cal per day
	residual:	{}
2	command:	we demand 2 ice creams
	parsed:	you will gain 469 Cal
	residual:	{}
3	command:	i crave 2 ice creams and 5 chocolates
	parsed:	you will gain 1171 Cal
	residual:	{}
4	command:	you crave chocolate and milk
	parsed:	No, I do not. I am a machine.
	residual:	{}

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