refactor: cleanup unused, def => let

README.md

@@ -22,7 +22,11 @@ Hello, World!
 DONE:
 - Parsing, Compiling, Running(VM)
 - Intrinsic:
-  - `fun`, `do`, `print`, `if`
+  - Function definition: `fun`
+  - Variable definition: `let`
+  - Do blocks: `do`
+  - Printing: `print`
+  - Condition: `if`
   - Math: 
     - `+` , `add`
     - `-` , `sub`

blspc/src/compiler/compile.rs

@@ -66,7 +66,7 @@ impl Compiler {
                                     result.push(Instr::Jump { to: len(&else_) });
                                     result.append(&mut else_);
                                 },
-                                "def" => {
+                                "let" => {
                                     let var_name = match &cdr[0] {
                                         Symbol(ref name) => name.clone(),
                                         _ => return Err(format!("Expected variable name, got {}", cdr[0])),

blspc/src/vm/instr.rs

@@ -10,19 +10,9 @@ pub enum Type {
     Float(f64),
     Boolean(bool),
     String(String),
-    Symbol(String),
 }
 
 impl Type {
-    pub fn as_bool(&self) -> bool {
-        match self {
-            Type::Boolean(b) => *b,
-            Type::Int(i) => *i != 0,
-            Type::Float(f) => *f != 0.0,
-            Type::String(s) => !s.is_empty(),
-            _ => unreachable!(),
-        }
-    }
 
     pub fn is_null(&self) -> bool {
         match self {
@@ -48,7 +38,6 @@ impl Type {
                 false => "false".to_string(),
             },
             Type::String(s) => s.clone(),
-            _ => unreachable!(),
         }
     }
 }
@@ -117,7 +106,6 @@ impl Display for Type {
             Type::Float(fl)  => write!(f, ":{}", fl),
             Type::Boolean(b) => write!(f, ":{}", b),
             Type::String(s)  => write!(f, "$\"{}\"", s),
-            Type::Symbol(s)  => write!(f, "function_{}", s),
             _ => unreachable!(),
         }
     }

blspc/src/vm/vm.rs

@@ -7,7 +7,6 @@ pub enum Error {
     StackOverflow,
     UnknownFunction(String),
     UnknownFunctionCall(isize, isize),
-    UnknownVariable(String),
     InvalidAriphmeticOperation,
 }
 
@@ -18,7 +17,6 @@ impl Display for Error {
             Error::StackOverflow => write!(f, "Stack overflow"),
             Error::UnknownFunction(name) => write!(f, "Unknown function: {}", name),
             Error::UnknownFunctionCall(l, e) => write!(f, "Unknown function call at {}: {}", l, e),
-            Error::UnknownVariable(name) => write!(f, "Unknown variable: {}", name),
             Error::InvalidAriphmeticOperation => write!(f, "Invalid ariphmetic operation"),
         }
     }

example/var.blsp

@@ -1,3 +1,7 @@
-(fun main
-    (do (def name "Bobby")
-        (print name)))
+(fun return_true true)
+
+(fun main (do
+    (let name "John")
+    (if (return_true)
+        (print name)
+        (print "no"))))