From 05bfabb1d4a8c2a4dd95208eb3e5fbf5fb08e588 Mon Sep 17 00:00:00 2001
From: PaddiM8 <paddim8@pm.me>
Date: Sat, 13 Jun 2020 20:06:21 +0200
Subject: [PATCH] Made it possible for the inverter to invert expressions with
 function calls.

---
 kalk/src/inverter.rs | 50 ++++++++++++++++++++++++++++++++++----------
 kalk/src/parser.rs   |  2 +-
 2 files changed, 40 insertions(+), 12 deletions(-)

diff --git a/kalk/src/inverter.rs b/kalk/src/inverter.rs
index d79486c..11d0b2d 100644
--- a/kalk/src/inverter.rs
+++ b/kalk/src/inverter.rs
@@ -1,21 +1,29 @@
-use crate::ast::Expr;
+use crate::ast::{Expr, Stmt};
 use crate::lexer::TokenKind;
+use crate::symbol_table::SymbolTable;
 
 impl Expr {
-    pub fn invert(&self) -> Self {
+    pub fn invert(&self, symbol_table: &mut SymbolTable) -> Self {
         match self {
-            Expr::Binary(left, op, right) => invert_binary(&left, op, &right),
+            Expr::Binary(left, op, right) => invert_binary(symbol_table, &left, op, &right),
             Expr::Unary(op, expr) => invert_unary(op, &expr),
             Expr::Unit(identifier, expr) => invert_unit(&identifier, &expr),
-            Expr::Var(identifier) => invert_value(self),
+            Expr::Var(_) => invert_value(self),
             Expr::Group(expr) => invert_group(&expr),
-            Expr::FnCall(identifier, expressions) => invert_fn_call(&identifier, expressions),
-            Expr::Literal(value) => invert_value(self),
+            Expr::FnCall(identifier, arguments) => {
+                invert_fn_call(symbol_table, &identifier, arguments)
+            }
+            Expr::Literal(_) => invert_value(self),
         }
     }
 }
 
-fn invert_binary(left: &Expr, op: &TokenKind, right: &Expr) -> Expr {
+fn invert_binary(
+    symbol_table: &mut SymbolTable,
+    left: &Expr,
+    op: &TokenKind,
+    right: &Expr,
+) -> Expr {
     let op_inv = match op {
         TokenKind::Plus => TokenKind::Minus,
         TokenKind::Minus => TokenKind::Plus,
@@ -24,7 +32,11 @@ fn invert_binary(left: &Expr, op: &TokenKind, right: &Expr) -> Expr {
         _ => unreachable!(),
     };
 
-    Expr::Binary(Box::new(right.invert()), op_inv, Box::new(left.invert()))
+    Expr::Binary(
+        Box::new(right.invert(symbol_table)),
+        op_inv,
+        Box::new(left.invert(symbol_table)),
+    )
 }
 
 fn invert_unary(op: &TokenKind, expr: &Expr) -> Expr {
@@ -35,7 +47,8 @@ fn invert_unary(op: &TokenKind, expr: &Expr) -> Expr {
     }
 }
 
-fn invert_unit(identifier: &str, expr: &Expr) -> Expr {
+// Not necessary yet
+fn invert_unit(_identifier: &str, _expr: &Expr) -> Expr {
     unimplemented!()
 }
 
@@ -43,8 +56,23 @@ fn invert_group(expr: &Expr) -> Expr {
     invert_value(expr)
 }
 
-fn invert_fn_call(identifier: &str, expressions: &Vec<Expr>) -> Expr {
-    unimplemented!()
+fn invert_fn_call(symbol_table: &mut SymbolTable, identifier: &str, arguments: &Vec<Expr>) -> Expr {
+    let (parameters, body) =
+        if let Some(Stmt::FnDecl(_, parameters, body)) = symbol_table.get_fn(identifier).cloned() {
+            (parameters, body)
+        } else {
+            panic!(); // TODO: Error checking
+        };
+
+    let mut parameters_iter = parameters.iter();
+    for argument in arguments {
+        symbol_table.insert(Stmt::VarDecl(
+            parameters_iter.next().unwrap().to_string(),
+            Box::new(argument.clone()),
+        ));
+    }
+
+    body.invert(symbol_table)
 }
 
 fn invert_value(expr: &Expr) -> Expr {
diff --git a/kalk/src/parser.rs b/kalk/src/parser.rs
index bdf37db..a998799 100644
--- a/kalk/src/parser.rs
+++ b/kalk/src/parser.rs
@@ -187,7 +187,7 @@ fn parse_unit_decl_stmt(context: &mut Context) -> Result<Stmt, CalcError> {
     let stmt_inv = Stmt::UnitDecl(
         base_unit.clone(),
         identifier.value.clone(),
-        Box::new(def.invert()),
+        Box::new(def.invert(&mut context.symbol_table)),
     );
     let stmt = Stmt::UnitDecl(identifier.value, base_unit, Box::new(def));