fix: parameters converted in opposite order

Makefile

@@ -5,4 +5,4 @@ it:
 	@ chmod +x ${BINARY_NAME}
 
 ex: it
-	@ ./lambda.exe -v - < ./samples/simple.txt
+	@ ./lambda.exe - < ./samples/simple.txt

cmd/lambda/lambda.go

@@ -7,6 +7,8 @@ import (
 
 	"git.maximhutz.com/max/lambda/internal/cli"
 	"git.maximhutz.com/max/lambda/internal/config"
+	"git.maximhutz.com/max/lambda/pkg/convert"
+	"git.maximhutz.com/max/lambda/pkg/lambda"
 	"git.maximhutz.com/max/lambda/pkg/saccharine"
 )
 
@@ -16,8 +18,8 @@ func main() {
 	cli.HandleError(err)
 
 	logger := options.GetLogger()
-	logger.Info("Using program arguments.", "args", os.Args)
-	logger.Info("Parsed CLI options.", "options", options)
+	logger.Info("using program arguments", "args", os.Args)
+	logger.Info("parsed CLI options", "options", options)
 
 	input, err := options.Source.Pull()
 	cli.HandleError(err)
@@ -25,29 +27,32 @@ func main() {
 	// Parse tokens.
 	tokens, err := saccharine.GetTokens([]rune(input))
 	cli.HandleError(err)
-	logger.Info("Parsed tokens.", "tokens", tokens)
+	logger.Info("parsed tokens", "tokens", tokens)
 
 	// Turn tokens into syntax tree.
 	expression, err := saccharine.Parse(tokens)
 	cli.HandleError(err)
-	logger.Info("Parsed syntax tree.", "tree", expression)
+	logger.Info("parsed syntax tree", "tree", saccharine.Stringify(expression))
+
+	compiled := convert.SaccharineToLambda(expression)
+	logger.Info("compiled lambda expression", "tree", lambda.Stringify(compiled))
 
 	// Reduce expression.
 	start := time.Now()
 
 	if options.Explanation {
-		fmt.Println(saccharine.Stringify(expression))
+		fmt.Println(lambda.Stringify(compiled))
 	}
 
-	// for lambda.ReduceOnce(&expression) {
-	// 	logger.Info("Reduction.", "tree", saccharine.Stringify(expression))
-	// 	if options.Explanation {
-	// 		fmt.Println("    =", saccharine.Stringify(expression))
-	// 	}
-	// }
+	for lambda.ReduceOnce(&compiled) {
+		logger.Info("reduction", "tree", lambda.Stringify(compiled))
+		if options.Explanation {
+			fmt.Println("    =", lambda.Stringify(compiled))
+		}
+	}
 
 	elapsed := time.Since(start).Milliseconds()
 
-	fmt.Println(saccharine.Stringify(expression))
+	fmt.Println(lambda.Stringify(compiled))
 	fmt.Fprintln(os.Stderr, "Time Spent:", elapsed, "ms")
 }

pkg/convert/saccharine_to_lambda.go

@@ -0,0 +1,52 @@
+package convert
+
+import (
+	"git.maximhutz.com/max/lambda/pkg/lambda"
+	"git.maximhutz.com/max/lambda/pkg/saccharine/ast"
+)
+
+type compileVisitor struct{}
+
+func (v compileVisitor) VisitAtom(n *ast.Atom) lambda.Expression {
+	return lambda.NewVariable(n.Name)
+}
+
+func (v compileVisitor) VisitAbstraction(n *ast.Abstraction) lambda.Expression {
+	result := ast.Visit(v, n.Body)
+
+	parameters := n.Parameters
+
+	// If the function has no parameters, it is a thunk. Lambda calculus still
+	// requires _some_ parameter exists, so generate one.
+	if len(parameters) == 0 {
+		freeVars := lambda.GetFreeVariables(result)
+		freshName := lambda.GenerateFreshName(freeVars)
+		parameters = append(parameters, freshName)
+	}
+
+	for i := len(parameters) - 1; i >= 0; i-- {
+		result = lambda.NewAbstraction(parameters[i], result)
+	}
+
+	return result
+}
+
+func (v compileVisitor) VisitApplication(n *ast.Application) lambda.Expression {
+	result := ast.Visit(v, n.Abstraction)
+
+	arguments := []lambda.Expression{}
+	for _, argument := range n.Arguments {
+		convertedArgument := ast.Visit(v, argument)
+		arguments = append(arguments, convertedArgument)
+	}
+
+	for _, argument := range arguments {
+		result = lambda.NewApplication(result, argument)
+	}
+
+	return result
+}
+
+func SaccharineToLambda(n ast.Expression) lambda.Expression {
+	return ast.Visit(&compileVisitor{}, n)
+}

samples/simple.txt

@@ -3,7 +3,7 @@
     (\add.
       (\mult.
         (\exp.
-          (exp (inc (inc (inc (inc (inc 0))))) (inc (inc (inc (inc (inc 0))))))
+          (exp (inc (inc (inc (inc 0)))) (inc (inc (inc (inc (inc 0))))))
           \n m.(m n)
         )
         \m n f.(m (n f))