feat(assembler): Implemented semantic analysis

1 files changed, 46 insertions, 0 deletions

diff --git a/assembler/src/parser/instruction.rs b/assembler/src/parser/instruction.rs
index c44c1de..18d67b7 100644
--- a/assembler/src/parser/instruction.rs
+++ b/assembler/src/parser/instruction.rs
@@ -1,5 +1,15 @@
 use super::{ Instruction, Address };
 
+#[derive(Debug)]
+pub(crate) enum ArgumentError {
+    UnknownInstruction,
+    TooMany,
+    TooFew,
+    NotLocation,
+    NotNumber,
+    NotString,
+}
+
 impl Instruction {
     fn new_subleq(a: &Address, b: &Address, c: &Address) -> Instruction {
         if let Address::Constants(_) = c {
@@ -11,6 +21,42 @@ impl Instruction {
         }
     }
 
+    fn check_args_len(&self, expected: usize) -> Result<(), ArgumentError> {
+        if self.args.len() < expected {
+            return Err(ArgumentError::TooFew);
+        }
+        else if self.args.len() > 3 {
+            return Err(ArgumentError::TooMany);
+        }
+        Ok(())
+    }
+
+    pub(crate) fn check_args(&self) -> Result<(), ArgumentError> {
+        match &*self.name {
+            "subleq" => {
+                self.check_args_len(3)?;
+
+                for arg in &self.args {
+                    if ! arg.is_location() {
+                        return Err(ArgumentError::NotLocation);
+                    }
+                }
+            },
+            "jmp" => {
+                self.check_args_len(1)?;
+
+                if ! self.args[0].is_location() {
+                    return Err(ArgumentError::NotLocation);
+                }
+            },
+            "add" => {
+                self.check_args_len(2)?;
+            },
+            _ => return Err(ArgumentError::UnknownInstruction),
+        }
+        Ok(())
+    }
+
     pub(crate) fn collapse(&mut self, next: usize) -> Vec<Instruction> {
         self.name = self.name.to_lowercase();
         static Z: Address = Address::Memory(0);