Make duplicate function definitions as compile-time errors

Author: weirdsmiley

src/ast.rs

@@ -1,6 +1,6 @@
 //! QAST is an abstract representation for quale language.
 use crate::attributes::Attributes;
-use crate::error::{QccError, QccErrorKind};
+use crate::error::{QccError, QccErrorKind, Result};
 use crate::lexer::Location;
 use crate::mangle::mangle_fns;
 use crate::types::Type;
@@ -190,8 +190,16 @@ impl ModuleAST {
         }
     }
 
-    pub(crate) fn append_function(&mut self, function: FunctionAST) {
-        self.functions.push(std::rc::Rc::new(function.into()));
+    pub(crate) fn append_function(&mut self, other: FunctionAST) -> Result<()> {
+        // TODO: Use HashSet to store functions in ModuleAST.
+        for function in &self.functions {
+            if function.as_ref().borrow().name == other.name {
+                return Err(QccErrorKind::DuplicateFunction.into());
+            }
+        }
+
+        self.functions.push(std::rc::Rc::new(other.into()));
+        Ok(())
     }
 
     #[inline]

src/error.rs

@@ -72,6 +72,7 @@ pub enum QccErrorKind {
     ExpectedIf,
     ExpectedOpenCurly,
     ExpectedCloseCurly,
+    DuplicateFunction,
 }
 
 impl Display for QccErrorKind {
@@ -125,6 +126,7 @@ impl Display for QccErrorKind {
                 ExpectedIf => "expected 'if'",
                 ExpectedOpenCurly => "expected '{'",
                 ExpectedCloseCurly => "expected '}'",
+                DuplicateFunction => "duplicate function",
             }
         })(self))
     }

src/parser.rs

@@ -751,7 +751,19 @@ impl Parser {
                 }
             } else if self.lexer.is_token(Token::Hash) || self.lexer.is_token(Token::Function) {
                 match self.parse_function() {
-                    Ok(f) => this.append_function(f),
+                    Ok(f) => {
+                        let name = f.get_name().clone();
+                        let loc = f.get_loc().clone();
+
+                        match this.append_function(f) {
+                            Ok(_) => {}
+                            Err(e) => {
+                                // TODO: Improve information.
+                                seen_errors = true;
+                                qcceprintln!("{} {} {}", e, name, loc);
+                            }
+                        }
+                    }
                     Err(e) => {
                         seen_errors = true;
 

tests/test_duplicate_functions.ql

@@ -0,0 +1,8 @@
+fn double(x: f64) : f64 {
+  return 2 * x;
+}
+
+fn double(x: f64) : f64 { // ERROR
+  return 2 * x;
+}
+

tests/tests.rs

@@ -298,6 +298,8 @@ fn test_ast_gen() -> Result<(), Box<dyn std::error::Error>>  {
 "|_ test_empty			// @test_empty.ql:1:1
 ");
 
+    // test!("tests/test_duplicate_functions.ql", "");
+
     test!("examples/toss.ql",
 "|_ toss			// @toss.ql:1:1
   |_ fn toss$sin (x: float64) : float64		// @toss.ql:2:4