From 0760cfbd4983ce0832b5b496e8925867c80538dd Mon Sep 17 00:00:00 2001
From: Huzaifa Raghav <huzaifaraghav2000@gmail.com>
Date: Thu, 18 Apr 2024 23:03:47 +0800
Subject: [PATCH] Add wait and post to parser

---
 compiler/oxidate/src/compiler.rs |  2 ++
 src/lexer/src/lib.rs             | 19 ++++++++++
 src/parser/src/lib.rs            | 62 +++++++++++++++++++++++++++++++-
 src/parser/src/structs.rs        |  8 +++++
 src/types/src/type_checker.rs    | 10 ++++++
 5 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/compiler/oxidate/src/compiler.rs b/compiler/oxidate/src/compiler.rs
index 4d35ba5..695eff1 100644
--- a/compiler/oxidate/src/compiler.rs
+++ b/compiler/oxidate/src/compiler.rs
@@ -326,6 +326,8 @@ impl Compiler {
                 // push RESET
                 arr.push(ByteCode::RESET(bytecode::FrameType::CallFrame))
             }
+            Decl::WaitStmt(_) => {}
+            Decl::PostStmt(_) => {}
         };
 
         Ok(())
diff --git a/src/lexer/src/lib.rs b/src/lexer/src/lib.rs
index a48d6b6..28df9d0 100644
--- a/src/lexer/src/lib.rs
+++ b/src/lexer/src/lib.rs
@@ -145,6 +145,12 @@ pub enum Token {
     #[token("join")]
     Join,
 
+    #[token("wait")]
+    Wait,
+
+    #[token("post")]
+    Post,
+
     #[token("false", |_| false)]
     #[token("true", |_| true)]
     Bool(bool),
@@ -222,6 +228,8 @@ impl Token {
             Self::FnDeclReturn => "->".to_string(),
             Self::Spawn => "spawn".to_string(),
             Self::Join => "join".to_string(),
+            Self::Wait => "wait".to_string(),
+            Self::Post => "post".to_string(),
         }
     }
 }
@@ -636,4 +644,15 @@ mod test {
         assert_eq!(lexer.next().unwrap().unwrap(), Token::Spawn);
         assert_eq!(lexer.next().unwrap().unwrap(), Token::Join);
     }
+
+    #[test]
+    fn test_lex_wait_post() {
+        let t = r"
+        wait post
+        ";
+        let mut lexer = Token::lexer(t);
+
+        assert_eq!(lexer.next().unwrap().unwrap(), Token::Wait);
+        assert_eq!(lexer.next().unwrap().unwrap(), Token::Post);
+    }
 }
diff --git a/src/parser/src/lib.rs b/src/parser/src/lib.rs
index 59e0db0..a237a42 100644
--- a/src/parser/src/lib.rs
+++ b/src/parser/src/lib.rs
@@ -241,6 +241,25 @@ impl<'inp> Parser<'inp> {
                     Err(ParseError::new("join expected variable for thread to join"))
                 }
             }
+            // wait sem;
+            Token::Wait => {
+                self.advance();
+                let sem = self.parse_expr(0)?.to_expr()?;
+                if let Expr::Symbol(sem_sym) = sem {
+                    Ok(Decl::WaitStmt(sem_sym))
+                } else {
+                    Err(ParseError::new("wait expected semaphore variable"))
+                }
+            }
+            Token::Post => {
+                self.advance();
+                let sem = self.parse_expr(0)?.to_expr()?;
+                if let Expr::Symbol(sem_sym) = sem {
+                    Ok(Decl::PostStmt(sem_sym))
+                } else {
+                    Err(ParseError::new("post expected semaphore variable"))
+                }
+            }
             // if not is_loop, error
             Token::Break => {
                 if !self.is_loop {
@@ -397,7 +416,7 @@ mod tests {
     }
 
     #[test]
-    fn test_parse_spawn_join() {
+    fn test_parse_concurrency() {
         let t = r"
         let t = spawn func();
         spawn f2();
@@ -416,5 +435,46 @@ mod tests {
         let res = join t;
         ";
         test_parse(t, "let t = spawn func();let res = join t;");
+
+        // wait and post
+        let t = r"
+        let sem = sem_create();
+        wait sem;
+        post sem;
+        ";
+        test_parse(t, "let sem = sem_create();wait sem;post sem;");
+
+        let t = r"
+        wait 2+2;
+        ";
+        test_parse_err(t, "expected semaphore variable", true);
+
+        let t = r"
+        post 2+2;
+        ";
+        test_parse_err(t, "expected semaphore variable", true);
+
+        // can't assign wait/post
+        let t = r"
+        let x = wait sem;
+        ";
+        test_parse_err(t, "wait is not an expression", true);
+
+        // can't assign wait/post
+        let t = r"
+        let x = post sem;
+        ";
+        test_parse_err(t, "post is not an expression", true);
+
+        // must be stmt with semi
+        let t = r"
+         wait sem
+         ";
+        test_parse_err(t, "Expected semicolon", true);
+
+        let t = r"
+         post sem
+         ";
+        test_parse_err(t, "Expected semicolon", true);
     }
 }
diff --git a/src/parser/src/structs.rs b/src/parser/src/structs.rs
index 1d1fc43..4fbe667 100644
--- a/src/parser/src/structs.rs
+++ b/src/parser/src/structs.rs
@@ -261,6 +261,10 @@ pub enum Decl {
     BreakStmt,
     // only inside fn
     ReturnStmt(Option<Expr>),
+    // wait sem; - stmt only
+    WaitStmt(String),
+    // post sem; - stmt only
+    PostStmt(String),
 }
 
 impl Decl {
@@ -284,6 +288,8 @@ impl Decl {
             Self::LoopStmt(_) => Err(ParseError::new("loop is not an expression")),
             Self::BreakStmt => Err(ParseError::new("break is not an expression")),
             Self::ReturnStmt(_) => Err(ParseError::new("return is not an expression")),
+            Self::WaitStmt(_) => Err(ParseError::new("wait is not an expression")),
+            Self::PostStmt(_) => Err(ParseError::new("post is not an expression")),
             Self::ExprStmt(expr) => Ok(expr.clone()),
         }
     }
@@ -326,6 +332,8 @@ impl Display for Decl {
                 };
                 format!("{}{}", Token::Return, str)
             }
+            Decl::WaitStmt(sym) => format!("wait {}", sym),
+            Decl::PostStmt(sym) => format!("post {}", sym),
         };
 
         write!(f, "{}", string)
diff --git a/src/types/src/type_checker.rs b/src/types/src/type_checker.rs
index 2a5dd6b..9e75aee 100644
--- a/src/types/src/type_checker.rs
+++ b/src/types/src/type_checker.rs
@@ -449,6 +449,16 @@ impl<'prog> TypeChecker<'prog> {
                 must_break: true,
                 must_return: true,
             }),
+            Decl::WaitStmt(_) => Ok(CheckResult {
+                ty: Type::Unit,
+                must_break: false,
+                must_return: false,
+            }),
+            Decl::PostStmt(_) => Ok(CheckResult {
+                ty: Type::Unit,
+                must_break: false,
+                must_return: false,
+            }),
         }
 
         // Ok(())