restructuring things

src/compiler/assembly_pass.rs

@@ -5,7 +5,7 @@ use crate::compiler::assembly_pass::Op::{
     Dup, Equal, Get, Goto, GotoIf, GotoIfNot, Greater, GreaterEqual, Less, LessEqual, ListGet,
     Multiply, Negate, Not, NotEqual, Or, Pop, Print, Return, Shr, Subtract,
 };
-use crate::compiler::ast_pass::Expression::{IfExpression, NamedParameter};
+use crate::compiler::ast_pass::Expression::{IfElseExpression, IfExpression, NamedParameter};
 use crate::compiler::ast_pass::{Expression, Function, Parameter, Statement};
 use crate::compiler::tokens::TokenType;
 use crate::compiler::tokens::TokenType::Unknown;
@@ -186,38 +186,6 @@ impl AsmPass {
             Statement::GuardStatement { .. } => {
                 unimplemented!("guard statement")
             }
-            Statement::ForStatement {
-                loop_var,
-                range,
-                body,
-            } => {
-                // 1. step var index
-                let step_const_index = self.emit_constant(Value::I64(1));
-                // 2. range expression
-                self.compile_expression(namespace, range, symbols, registry)?;
-                //save the constants for lower and upper bounds of the range
-                let start_index = self.chunk.constants.len() - 1;
-                let end_index = self.chunk.constants.len() - 2;
-
-                let name = loop_var.lexeme.as_str();
-                let loop_var_name_index = self.chunk.add_var(&loop_var.token_type, name);
-                self.vars.insert(name.to_string(), loop_var_name_index);
-
-                // 3. start index
-                self.emit(Constant(start_index));
-                self.emit(Assign(loop_var_name_index));
-
-                let return_addr = self.chunk.code.len();
-                self.compile_statements(body, symbols, registry, namespace)?;
-                self.emit(Get(loop_var_name_index));
-                self.emit(Constant(step_const_index));
-                self.emit(Add);
-                self.emit(Assign(loop_var_name_index));
-                self.emit(Constant(end_index));
-                self.emit(Get(loop_var_name_index));
-                self.emit(GreaterEqual);
-                self.emit(GotoIf(return_addr));
-            }
         }
         Ok(())
     }
@@ -233,6 +201,22 @@ impl AsmPass {
             IfExpression {
                 condition,
                 then_branch,
+            } => {
+                self.compile_expression(namespace, condition, symbols, registry)?;
+
+                self.emit(Dup);
+                self.emit(GotoIfNot(0)); // placeholder
+                let goto_addr1 = self.chunk.code.len() - 1;
+                self.emit(Pop);
+                self.compile_statements(then_branch, symbols, registry, namespace)?;
+                self.emit(Goto(0));
+                let goto_addr2 = self.chunk.code.len() - 1; // placeholder
+                self.chunk.code[goto_addr1] = GotoIfNot(self.chunk.code.len());
+                self.chunk.code[goto_addr2] = Op::Goto(self.chunk.code.len());
+            }
+            IfElseExpression {
+                condition,
+                then_branch,
                 else_branch,
             } => {
                 self.compile_expression(namespace, condition, symbols, registry)?;
@@ -455,6 +439,38 @@ impl AsmPass {
                 self.compile_expression(namespace, upper, symbols, registry)?;
                 self.compile_expression(namespace, lower, symbols, registry)?;
             }
+            Expression::ForStatement {
+                loop_var,
+                range,
+                body,
+            } => {
+                // 1. step var index
+                let step_const_index = self.emit_constant(Value::I64(1));
+                // 2. range expression
+                self.compile_expression(namespace, range, symbols, registry)?;
+                //save the constants for lower and upper bounds of the range
+                let start_index = self.chunk.constants.len() - 1;
+                let end_index = self.chunk.constants.len() - 2;
+
+                let name = loop_var.lexeme.as_str();
+                let loop_var_name_index = self.chunk.add_var(&loop_var.token_type, name);
+                self.vars.insert(name.to_string(), loop_var_name_index);
+
+                // 3. start index
+                self.emit(Constant(start_index));
+                self.emit(Assign(loop_var_name_index));
+
+                let return_addr = self.chunk.code.len();
+                self.compile_statements(body, symbols, registry, namespace)?;
+                self.emit(Get(loop_var_name_index));
+                self.emit(Constant(step_const_index));
+                self.emit(Add);
+                self.emit(Assign(loop_var_name_index));
+                self.emit(Constant(end_index));
+                self.emit(Get(loop_var_name_index));
+                self.emit(GreaterEqual);
+                self.emit(GotoIf(return_addr));
+            }
         }
         Ok(())
     }

src/compiler/ast_pass.rs

@@ -1,7 +1,7 @@
 use crate::builtins::globals::GLOBAL_FUNCTIONS;
 use crate::compiler::ast_pass::Expression::{
-    Assignment, FieldGet, FunctionCall, IfExpression, LetExpression, ListGet, MapGet, MethodCall,
+    Assignment, FieldGet, FunctionCall, IfElseExpression, IfExpression, LetExpression, ListGet,
-    NamedParameter, Stop, Variable,
+    MapGet, MethodCall, NamedParameter, Stop, Variable,
 };
 use crate::compiler::tokens::TokenType::{
     Bang, Bool, Char, Colon, DateTime, Dot, Else, Eof, Eol, Equal, False, FloatingPoint, Fn, For,
@@ -128,7 +128,7 @@ impl AstCompiler {
         } else if self.match_token(&[TokenType::Pipe]) {
             self.guard_declaration(symbol_table)
         } else {
-            self.statement(symbol_table)
+            self.expr_statement(symbol_table)
         }
     }
 
@@ -284,15 +284,26 @@ impl AstCompiler {
         Ok(Statement::FunctionStmt { function })
     }
 
-    fn statement(&mut self, symbol_table: &mut SymbolTable) -> Stmt {
+    fn inc_indent(&mut self) {
-        if self.match_token(&[For]) {
+        self.indent.push(self.indent.last().unwrap() + 1);
-            self.for_statement(symbol_table)
-        } else {
-            self.expr_statement(symbol_table)
-        }
     }
 
-    fn for_statement(&mut self, symbol_table: &mut SymbolTable) -> Stmt {
+    fn expr_statement(&mut self, symbol_table: &mut SymbolTable) -> Stmt {
+        let expr = if self.match_token(&[For]) {
+            self.for_expression(symbol_table)?
+        } else if self.match_token(&[Let]) {
+            let expr = self.let_exp(symbol_table)?;
+            if !self.is_at_end() {
+                self.consume(&Eol, Expected("end of line after expression."))?;
+            }
+            expr
+        } else {
+            self.expression(symbol_table)?
+        };
+        Ok(Statement::ExpressionStmt { expression: expr })
+    }
+
+    fn for_expression(&mut self, symbol_table: &mut SymbolTable) -> Expr {
         let loop_var = self.consume(&Identifier, Expected("loop variable name."))?;
         self.consume(&In, Expected("'in' after loop variable name."))?;
         let range = self.expression(symbol_table)?;
@@ -301,27 +312,14 @@ impl AstCompiler {
         self.inc_indent();
         let body = self.compile(symbol_table)?;
 
-        Ok(Statement::ForStatement {
+        Ok(Expression::ForStatement {
             loop_var,
-            range,
+            range: Box::new(range),
             body,
         })
     }
 
-    fn inc_indent(&mut self) {
-        self.indent.push(self.indent.last().unwrap() + 1);
-    }
-
-    fn expr_statement(&mut self, symbol_table: &mut SymbolTable) -> Stmt {
-        let expr = self.let_exp(symbol_table)?;
-        if !self.is_at_end() {
-            self.consume(&Eol, Expected("end of line after expression."))?;
-        }
-        Ok(Statement::ExpressionStmt { expression: expr })
-    }
-
     fn let_exp(&mut self, symbol_table: &mut SymbolTable) -> Expr {
-        if self.match_token(&[Let]) {
         if self.peek().token_type.is_type() {
             return Err(self.raise(CompilerError::KeywordNotAllowedAsIdentifier(
                 self.peek().token_type.clone(),
@@ -358,9 +356,6 @@ impl AstCompiler {
         } else {
             Err(self.raise(UninitializedVariable))?
         }
-        } else {
-            self.expression(symbol_table)
-        }
     }
 
     fn expression(&mut self, symbol_table: &mut SymbolTable) -> Expr {
@@ -499,20 +494,23 @@ impl AstCompiler {
             self.inc_indent();
             let then_branch = self.compile(symbol_table)?;
 
-            let else_branch = if self.check(&Else) {
+            if self.check(&Else) {
                 self.consume(&Else, Expected("'else' after if condition."))?;
                 self.consume(&Colon, Expected("':' after 'else'."))?;
 
                 self.inc_indent();
-                Some(self.compile(symbol_table)?)
+
+                Ok(IfElseExpression {
+                    condition: Box::new(condition),
+                    then_branch,
+                    else_branch: Some(self.compile(symbol_table)?),
+                })
             } else {
-                None
-            };
                 Ok(IfExpression {
                     condition: Box::new(condition),
                     then_branch,
-                else_branch,
                 })
+            }
         } else {
             self.get(symbol_table)
         }
@@ -854,11 +852,6 @@ pub enum Statement {
         if_expr: Expression,
         then_expr: Expression,
     },
-    ForStatement {
-        loop_var: Token,
-        range: Expression,
-        body: Vec<Statement>,
-    },
 }
 
 impl Statement {
@@ -868,7 +861,6 @@ impl Statement {
             Statement::FunctionStmt { function, .. } => function.name.line,
             Statement::ObjectStmt { name, .. } => name.line,
             Statement::GuardStatement { if_expr, .. } => if_expr.line(),
-            Statement::ForStatement { loop_var, .. } => loop_var.line,
         }
     }
 }
@@ -973,6 +965,10 @@ pub enum Expression {
     IfExpression {
         condition: Box<Expression>,
         then_branch: Vec<Statement>,
+    },
+    IfElseExpression {
+        condition: Box<Expression>,
+        then_branch: Vec<Statement>,
         else_branch: Option<Vec<Statement>>,
     },
     LetExpression {
@@ -980,6 +976,11 @@ pub enum Expression {
         var_type: TokenType,
         initializer: Box<Expression>,
     },
+    ForStatement {
+        loop_var: Token,
+        range: Box<Expression>,
+        body: Vec<Statement>,
+    },
 }
 
 impl Expression {
@@ -1002,7 +1003,9 @@ impl Expression {
             ListGet { .. } => 0,
             FieldGet { .. } => 0,
             IfExpression { condition, .. } => condition.line(),
+            IfElseExpression { condition, .. } => condition.line(),
             LetExpression { name, .. } => name.line,
+            Expression::ForStatement { loop_var, .. } => loop_var.line,
         }
     }
 }

src/symbol_builder.rs

@@ -2,11 +2,7 @@ use crate::compiler::ast_pass::{Expression, Parameter, Statement};
 use crate::builtins::lookup;
 use crate::errors::CompilerError;
 use crate::errors::CompilerError::{IncompatibleTypes, UndeclaredVariable};
-use crate::compiler::tokens::TokenType::{
+use crate::compiler::tokens::TokenType::{Bool, DateTime, F32, F64, FloatingPoint, Greater, GreaterEqual, I32, I64, Integer, Less, LessEqual, ListType, MapType, Minus, ObjectType, Plus, SignedInteger, StringType, U32, U64, Unknown, UnsignedInteger, Void};
-    Bool, DateTime, F32, F64, FloatingPoint, Greater, GreaterEqual, I32, I64, Integer, Less,
-    LessEqual, ListType, MapType, Minus, ObjectType, Plus, SignedInteger, StringType, U32, U64,
-    Unknown, UnsignedInteger,
-};
 use crate::compiler::tokens::{Token, TokenType};
 use log::debug;
 use std::collections::HashMap;
@@ -218,13 +214,14 @@ pub fn infer_type(expr: &Expression, symbols: &HashMap<String, Symbol>) -> Token
             }
         }
         Expression::Stop { .. } => Unknown,
-        // Expression::PathMatch { .. } => Unknown,
         Expression::NamedParameter { .. } => Unknown,
         Expression::ListGet { .. } => Unknown,
         Expression::MapGet { .. } => Unknown,
         Expression::FieldGet { .. } => Unknown,
         Expression::Range { lower, .. } => infer_type(lower, symbols),
         Expression::IfExpression {  .. } => Unknown,
-        Expression::LetExpression { initializer,.. } => infer_type(initializer, symbols),
+        Expression::IfElseExpression {  .. } => Unknown,
+        Expression::LetExpression { .. } => Void,
+        Expression::ForStatement { .. } => Void,
     }
 }