Added comments for style.

Cargo.toml

@@ -6,6 +6,3 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-
-[profile.dev]
-debug=true

src/codegen/fasm.rs

@@ -1,9 +1,14 @@
 use crate::parse::ast::*;
 
 pub fn fasm_codegen(exprs: &Vec<Expr>, not_a_function: bool) -> String {
-    let mut asm_text = String::new();
+    // Define asm_func, used for functions.
+    let mut asm_func = String::new();
+    // Define asm_data, used for variables.
     let mut asm_data = String::new();
+    // Define asm_start, used for the entry point.
     let mut asm_start = String::new();
+
+    // If not_a_function, push necessary headers to the asm_start variable.
     if not_a_function {
 	asm_start.push_str("format ELF64 executable 3\n");
 	asm_start.push_str("segment readable executable\n");
@@ -11,11 +16,12 @@ pub fn fasm_codegen(exprs: &Vec<Expr>, not_a_function: bool) -> String {
 	asm_start.push_str("_start:\n");
 	asm_data.push_str("\nsegment readable writable\n");
     }
-    
-    for expr in exprs.iter() {
-        // println!("{:?}", expr);
 
+    // Iterate over expressions.
+    for expr in exprs.iter() {
+	// Use patern matching on `expr`.
 	match expr {
+	    // If the expression is a math expression.
 	    Expr::MathExpr(e) => {
 		asm_start.push_str(format!("\tmov r10, {}\n", e.left.unwrap()).as_str());
 		asm_start.push_str(format!("\tmov r11, {}\n", e.right.unwrap()).as_str());
@@ -24,23 +30,30 @@ pub fn fasm_codegen(exprs: &Vec<Expr>, not_a_function: bool) -> String {
 		    MathOperator::OP_ADD  => {
 			asm_start.push_str("\tadd r10, r11\n");
 			asm_start.push_str("\tmov rax, r10\n");
+			// r10 ← r10 + r11; rax ← r10;
+			// The sum will now be stored in the %rax register.
 		    },
 		    // If the operator is multiplication.
 		    MathOperator::OP_MULT => {
 			asm_start.push_str("\timul r10, r11\n");
 			asm_start.push_str("\tmov rax, r10\n");
+			// r10 ← r10 * r11; rax ← r10;
+			// The product will now be stored in the %rax register.
 		    },
 		    // If the operator is division.
 		    MathOperator::OP_DIV  => {
 			asm_start.push_str("\tmov rax, r10\n");
 			asm_start.push_str("\txor rdx, rdx\n");
 			asm_start.push_str("\tidiv r11\n");
-			// The quotient is now stored in %rax.
+			// rax ← r10; rdx ← 0; rax ← concat(rax, rdx) / r11;
+			// The quotient will now be stored in the %rax register.
 		    },
 		    // If the operators is subtraction.
 		    MathOperator::OP_SUB  => {
 			asm_start.push_str("\tsub r10, r11\n");
 			asm_start.push_str("\tmov rax, r10\n");
+			// r10 ← r10 - r11; rax ← r10;
+			// The difference will now be stored in the %rax register.
 		    },
 		    // If the operator is modulo.
 		    MathOperator::OP_MOD  => {
@@ -48,73 +61,89 @@ pub fn fasm_codegen(exprs: &Vec<Expr>, not_a_function: bool) -> String {
 			asm_start.push_str("\txor rdx, rdx\n");
 			asm_start.push_str("\tidiv r11\n");
 			asm_start.push_str("\tmov rax, rdx\n");
+			// rax ← r10; rdx ← 0; rdx ← concat(rax, rdx) % r11; rax ← rdx;
 			// The remainder will now be stored in the %rax register.
 		    }
 		}
 	    },
 
+	    // If the expression is a function call.
 	    Expr::FunCall(e) => {
 		for (i, p) in e.params.iter().enumerate() {
 		    match i {
 			0 => {
-			    // First parameter. Put in %rdi.
-			    asm_start.push_str(format!("\tmov rdi, {}\n", p.unwrap()).as_str());
+			    // First parameter. Put in %rdi.←		    asm_start.push_str(format!("\tmov rdi, {}\n", p.unwrap()).as_str());
+			    // rdi ← e.params[0];
 			},
 
 			1 => {
 			    // Second parameter. Put in %rsi.
 			    asm_start.push_str(format!("\tmov rsi, {}\n", p.unwrap()).as_str());
+			    // rsi ← e.params[1];
 			},
 
 			2 => {
 			    // Third parameter. Put in %rdx.
 			    asm_start.push_str(format!("\tmov rdx, {}\n", p.unwrap()).as_str());
+			    // rdx ← e.params[2];
 			},
 
 			3 => {
 			    // Fourth parameter. Put in %rcx.
 			    asm_start.push_str(format!("\tmov rcx, {}\n", p.unwrap()).as_str());
+			    // rcx ← e.params[3];
 			},
 
 			4 => {
 			    // Fifth parameter. Put in %r8.
 			    asm_start.push_str(format!("\tmov r8, {}\n", p.unwrap()).as_str());
+			    // r8 ← e.params[4];
 			},
 
 			5 => {
 			    // Sixth parameter. Put in %r9.
 			    asm_start.push_str(format!("\tmov r9, {}\n", p.unwrap()).as_str());
+			    // r9 ← e.params[5];
 			},
 
 			_ => {
 			    // Parameters after the sixth parameter are pushed to the stack.
 			    asm_start.push_str(format!("\tpush {}\n", p.unwrap()).as_str());
+			    // STACK_TOP ← e.params[(6+)];
 			}
 		    }
 		}
 
+		// Call the function.
 		asm_start.push_str(format!("\tcall {}\n", e.name).as_str());
 	    },
 
+	    // Define a global variable.
 	    Expr::VarDefinition(e) => {
+		// Define a 64-bit variable.
 		asm_data.push_str(format!("\t{} dq {}", e.name, e.value.unwrap()).as_str());
 	    },
 
+	    // Breakpoint.
 	    Expr::Breakpoint       => {
+		// Write the interrupt for a debugger breakpoint.
 		asm_start.push_str("\tint3\n");
 	    },
 
 	    Expr::Return(e)        => {
-		asm_start.push_str(format!("mov rax, {}", e.unwrap()).as_str());
+		asm_start.push_str(format!("mov [rbp - 8], {}", e.unwrap()).as_str());
 	    },
 
             Expr::FunDefinition(e) => {
-                asm_text.push_str(format!("{}:\n", e.name).as_str());
-	        asm_text.push_str(fasm_codegen(&e.contents, false).as_str());
-                asm_text.push_str("\tret\n");
-            }
+                asm_func.push_str(format!("{}:\n", e.name).as_str());
+	        asm_func.push_str(fasm_codegen(&e.contents, false).as_str());
+                asm_func.push_str("\tret\n");
+            },
 
-	    _ => break,
+	    _ => unsafe {
+		let mut ptr = 0x00 as *mut u32;
+		::std::ptr::write(ptr, "GOREN IS MY NAME AND BREAKING MEMORY IS MY GAME");
+	    },
 	}
         
     }
@@ -125,6 +154,6 @@ pub fn fasm_codegen(exprs: &Vec<Expr>, not_a_function: bool) -> String {
         asm_start.push_str("\txor rdi, rdi   ; 0 is the exit code we want.\n");
         asm_start.push_str("\tsyscall        ; this is the instruction to actually perform the system call.\n");
     }
-    let asm = format!("{}{}{}", asm_start, asm_text, asm_data);
+    let asm = format!("{}{}{}", asm_start, asm_func, asm_data);
     asm
 }

src/parse/ast.rs

@@ -5,6 +5,7 @@ pub enum Expr<'a> {
     FunDefinition(FunDefinition<'a>),
     VarDefinition(VarDefinition<'a>),
     Return(Value<'a>),
+    If(IfStatement<'a>),
     Breakpoint
 }
 
@@ -77,6 +78,25 @@ pub enum Value<'a> {
     Number(u64),
 }
 
+#[derive(Debug)]
+pub struct IfStatement<'a> {
+    pub condition: Condition<'a>,
+    pub if_true: Vec<Expr<'a>>,
+}
+
+#[derive(Debug)]
+pub struct Condition<'a> {
+    pub left: Value<'a>,
+    pub right: Value<'a>,
+    pub between: COND_OP,
+}
+
+#[derive(Debug)]
+pub enum COND_OP {
+    EQ,
+    NE,
+}
+
 impl<'a> Value<'a> {
     pub fn unwrap(&self) -> String {
 	match self {