Working

2026-02-08 22:48:51 +01:00
parent ced43b76bf
commit 134ebc6dc6
11 changed files with 1278 additions and 1 deletions
--- a/src/ast.rs
+++ b/src/ast.rs
@ -0,0 +1,112 @@
+use std::fmt::Display;
+
+pub type Variable = String;
+
+#[derive(Clone, Debug)]
+pub struct Module
+{
+    pub clauses: Vec<Clause>,
+}
+
+#[derive(Clone, Debug)]
+pub struct Clause
+{
+    pub head: Predicate,
+    pub body: Option<Body>,
+}
+
+#[derive(Clone, Debug)]
+pub enum Body
+{
+    Term(Predicate),
+    And(Vec<Body>),
+    Or(Vec<Body>),
+}
+
+#[derive(Clone, Debug)]
+pub enum Predicate
+{
+    Variable(Variable), // Upercase variable like X
+    Fixed(String, Vec<Predicate>),
+}
+
+impl Display for Body
+{
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
+    {
+        match self
+        {
+            Body::Term(predicate) => write!(f, "{}", predicate),
+            Body::And(items) | Body::Or(items) =>
+            {
+                let len = items.len();
+                for (i, item) in items.iter().enumerate()
+                {
+                    write!(f, "{}", item)?;
+                    if i != len - 1
+                    {
+                        write!(f, ",")?;
+                    }
+                }
+                Ok(())
+            }
+        }
+    }
+}
+
+impl Display for Predicate
+{
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
+    {
+        match self
+        {
+            Predicate::Variable(variable) => write!(f, "{}", variable),
+            Predicate::Fixed(name, predicates) =>
+            {
+                write!(f, "{}", name)?;
+                if !predicates.is_empty()
+                {
+                    write!(f, "(")?;
+                    let len = predicates.len();
+                    for (i, predicate) in predicates.iter().enumerate()
+                    {
+                        write!(f, "{}", predicate)?;
+                        if i != len - 1
+                        {
+                            write!(f, ", ")?;
+                        }
+                    }
+                    write!(f, ")")
+                }
+                else
+                {
+                    Ok(())
+                }
+            }
+        }
+    }
+}
+
+impl Display for Clause
+{
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
+    {
+        write!(f, "{}", self.head)?;
+        self.body
+            .as_ref()
+            .map_or_else(|| Ok(()), |body| write!(f, ":- {}", body))?;
+        write!(f, ".")
+    }
+}
+
+impl Display for Module
+{
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result
+    {
+        for clause in self.clauses.iter()
+        {
+            writeln!(f, "{}", clause)?;
+        }
+        Ok(())
+    }
+}