M.V. Hutz
528956b033
Add a new interpreter option (-i debruijn) that uses De Bruijn indices for variable representation, eliminating the need for variable renaming during substitution. - Add -i flag to select interpreter (lambda or debruijn) - Create debruijn package with Expression types (Variable with index, Abstraction without parameter, Application) - Implement shift and substitute operations for De Bruijn indices - Add conversion functions between lambda and De Bruijn representations - Update CLI to support switching between interpreters - Add De Bruijn tests to verify all samples pass Closes #26
36 lines
749 B
Go
36 lines
749 B
Go
package debruijn
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import (
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"strconv"
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"strings"
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)
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type stringifyVisitor struct {
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builder strings.Builder
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}
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func (v *stringifyVisitor) VisitVariable(a *Variable) {
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v.builder.WriteString(strconv.Itoa(a.index))
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}
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func (v *stringifyVisitor) VisitAbstraction(f *Abstraction) {
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v.builder.WriteRune('\\')
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v.builder.WriteRune('.')
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f.body.Accept(v)
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}
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func (v *stringifyVisitor) VisitApplication(c *Application) {
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v.builder.WriteRune('(')
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c.abstraction.Accept(v)
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v.builder.WriteRune(' ')
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c.argument.Accept(v)
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v.builder.WriteRune(')')
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}
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// Stringify converts a De Bruijn expression to its string representation.
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func Stringify(e Expression) string {
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b := &stringifyVisitor{builder: strings.Builder{}}
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e.Accept(b)
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return b.builder.String()
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}
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