Wolfram Language Paclet Repository
Community-contributed installable additions to the Wolfram Language
Wolfram`Parser`Languages`Lambda`
LambdaSemantic  |
| is the algebra that compiles lambda terms to native Wolfram closures - an of builder functions keyed "Var" "App" "Abs" | |
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LambdaSemantic
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The three builders are: folds a name to the matching Wolfram ; is real application, ; builds a closure by renaming the bound variable to a fresh symbol so application is genuine beta-reduction and shadowing stays capture-safe.
"Var"
"App"
f[x]
"Abs"
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The fresh-symbol renaming is what makes shadowing safe: because terms are built bottom-up, an inner binder has replaced its own occurrences before an outer binder runs, so substitution never captures a shadowed variable.
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It is a drop-in swap for the abstract-syntax algebra: the same yields a standard tree over that algebra (run by ) and a closure over . The grammar is untouched; only the algebra differs.
LambdaSemantic
Examples
(4)
Basic Examples
(1)
In[1]:=
Keys
 | LambdaSemantic |
Out[1]=
{Var,App,Abs}
In[2]:=
 | LambdaSemantic |
Out[2]=
q
The builder is ordinary Wolfram application:
"App"
In[3]:=
| LambdaSemantic |
Out[3]=
f[x]
The other half of the dual design is the abstract-syntax algebra; the same grammar over it emits a standard tree instead of a closure, which runs:
In[4]:=
| LambdaAST |
Out[4]=
ContainerNode[String,{CallNode[CallNode[CallNode[LeafNode[Symbol,λ,],{LeafNode[Symbol,x,],CallNode[LeafNode[Symbol,λ,],{LeafNode[Symbol,x,],LeafNode[Symbol,x,Source{{1,8},{1,9}}]},Source{{1,8},{1,9}}]},Source{{1,8},{1,9}}],{LeafNode[Symbol,a,Source{{1,11},{1,12}}]},Source{{1,8},{1,12}}],{LeafNode[Symbol,b,Source{{1,13},{1,14}}]},Source{{1,8},{1,14}}]},Source{{1,8},{1,14}}]
Scope
(1)
Properties & Relations
(1)
Neat Examples
(1)
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