Wolfram/Parser | Paclet Repository

Wolfram`Parser`Languages`Calculator`

CalculatorSemantic

is the algebra - an

Association

of builder functions - that folds the calculator parse to a numeric or symbolic Wolfram value.

Details and Options

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CalculatorSemantic

is one of the two algebras the calculator grammar runs over. It is the meaningful, language-specific one: each builder maps a parsed construct directly to its arithmetic value. The neutral alternative is

ASTAlgebra

, which builds a standard syntax tree instead.

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It is a plain

Association

with three keys:

"Leaf"

"Binary"

, and

"Prefix"

CalculatorGrammar

's semantic actions look up these keys, so the algebra is the language's meaning - swap it and the same grammar means something else.

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"Leaf"

turns matched source text into a value by kind: an

"Integer"

folds with

FromDigits

, a

"Real"

with

ToExpression

, and anything else (a

"Symbol"

) becomes the matching Wolfram

Symbol

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"Binary"

maps an operator descriptor to the matching Wolfram operation (

);

"Prefix"

negates for

"-"

and is the identity otherwise.

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CalculatorEval

is just

CalculatorGrammar

[CalculatorSemantic]

packaged as a function. To get the standard tree for the same grammar, run it over

ASTAlgebra

instead.

Examples

(4)

Basic Examples

(1)

The algebra is an

Association

of builder functions, keyed by node role:

In[1]:=

Keys

CalculatorSemantic



Out[1]=

{Leaf,Binary,Prefix}

The

"Leaf"

builder interprets matched source text. An integer kind folds with

FromDigits

In[2]:=

CalculatorSemantic

["Leaf"]["Integer","42"]

Out[2]=

"Symbol"

leaf becomes the matching Wolfram

Symbol

, keeping the value open:

In[3]:=

CalculatorSemantic

["Leaf"]["Symbol","x"]

Out[3]=

The

"Binary"

builder maps an operator descriptor onto the Wolfram operation:

In[4]:=

CalculatorSemantic

["Binary"]["+",1,2]

Out[4]=

Scope

(1)



Properties & Relations

(1)



Neat Examples

(1)



SeeAlso

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RelatedGuides

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ParserZoo