feat: copied code over

pkg/repr/saccharine/expression.go

@@ -0,0 +1,59 @@
+package saccharine
+
+import (
+	"git.maximhutz.com/max/lambda/pkg/repr"
+)
+
+type Expression interface {
+	repr.Repr
+}
+
+var (
+	_ Expression = Abstraction{}
+	_ Expression = Application{}
+	_ Expression = Variable{}
+	_ Expression = Clause{}
+)
+
+/** ------------------------------------------------------------------------- */
+
+type Abstraction struct {
+	Parameters []string
+	Body       Expression
+}
+
+func NewAbstraction(parameter []string, body Expression) *Abstraction {
+	return &Abstraction{Parameters: parameter, Body: body}
+}
+
+/** ------------------------------------------------------------------------- */
+
+type Application struct {
+	Abstraction Expression
+	Arguments   []Expression
+}
+
+func NewApplication(abstraction Expression, arguments []Expression) *Application {
+	return &Application{Abstraction: abstraction, Arguments: arguments}
+}
+
+/** ------------------------------------------------------------------------- */
+
+type Variable struct {
+	Name string
+}
+
+func NewVariable(name string) *Variable {
+	return &Variable{Name: name}
+}
+
+/** ------------------------------------------------------------------------- */
+
+type Clause struct {
+	Statements []Statement
+	Returns    Expression
+}
+
+func NewClause(statements []Statement, returns Expression) *Clause {
+	return &Clause{Statements: statements, Returns: returns}
+}