Implement if

src/interface.rs

@@ -12,18 +12,7 @@ use crate::{token, tree, Result, Value, VariableMap};
 /// *See the [crate doc](index.html) for more examples and explanations of the expression format.*
 pub fn eval(string: &str) -> Result<Value> {
     let mut context = VariableMap::new();
-    let eval = eval_with_context(string, &mut context);
+    eval_with_context(string, &mut context)
-
-    match eval {
-        Ok(output) => {
-            if output.is_empty() {
-                Ok(Value::Map(context))
-            } else {
-                Ok(output)
-            }
-        }
-        Err(error) => Err(error),
-    }
 }
 
 /// Evaluate the given expression string with the given context.

src/macros/logic.rs

@@ -1,4 +1,4 @@
-use crate::{Error, Macro, MacroInfo, Result, Value, ValueType};
+use crate::{Error, Macro, MacroInfo, Result, Value, ValueType };
 
 
 pub struct Assert;
@@ -58,18 +58,54 @@ impl Macro for If {
     fn info(&self) -> MacroInfo<'static> {
         MacroInfo {
             identifier: "if",
-            description: "Evaluates the first argument. If true, it does the second argument. If false, it does the third argument",            
+            description: "Evaluates the first argument. If true, it does the second argument.",     
-            group: "general",
+            group: "logic",
+            inputs: vec![
+                ValueType::List(vec![
+                    ValueType::Boolean,
+                    ValueType::Any,
+                ]), 
+                ValueType::List(vec![
+                    ValueType::Function, 
+                    ValueType::Any,
+                ])],
+        }
+    }
+
+    fn run(&self, argument: &Value) -> Result<Value> {
+        let argument = argument.as_fixed_len_list(2)?;
+        let (condition, if_true) = (&argument[0], &argument[1]);
+        let condition = if let Ok(function) = condition.as_function() {
+            function.run()?.as_boolean()?
+        } else {
+            condition.as_boolean()?
+        };
+
+        if condition {
+            Ok(if_true.clone())
+        } else {
+            Ok(Value::Empty)
+        }
+
+    }
+}
+
+pub struct IfElse;
+
+impl Macro for IfElse {
+    fn info(&self) -> MacroInfo<'static> {
+        MacroInfo {
+            identifier: "if_else",
+            description: "Evaluates the first argument. If true, it does the second argument. If false, it does the third argument",            
+            group: "logic",
             inputs: vec![
                 ValueType::List(vec![
                     ValueType::Boolean,
                     ValueType::Any,
-                    ValueType::Any
                 ]), 
                 ValueType::List(vec![
                     ValueType::Function, 
                     ValueType::Any,
-                    ValueType::Any
                 ])],
         }
     }

src/macros/mod.rs

@@ -40,7 +40,7 @@ pub mod time;
 ///
 /// This list is used to match identifiers with macros and to provide info to
 /// the shell.
-pub const MACRO_LIST: [&'static dyn Macro; 56] = [
+pub const MACRO_LIST: [&'static dyn Macro; 57] = [
     &collections::Count,
     &collections::CreateTable,
     &collections::Get,
@@ -80,6 +80,7 @@ pub const MACRO_LIST: [&'static dyn Macro; 56] = [
     &gui::Plot,
     &gui::Gui,
     &logic::If,
+    &logic::IfElse,
     &logic::Loop,
     &network::Download,
     &package_management::CoprRepositories,

src/value/variable_map.rs

@@ -68,9 +68,6 @@ impl VariableMap {
                 if argument.is_empty() {
                     return self.call_function(function_identifier, &value);
                 }
-
-                let value_type = value.value_type();
-
                 let list = Value::List(vec![value, argument.clone()]);
 
                 return self.call_function(function_identifier, &list);

tests/logic.rs

@@ -20,20 +20,20 @@ fn r#if() {
     assert_eq!(Value::Integer(1), value);
 
     let value = eval("if(false, 1)").unwrap();
-    assert!(value.is_empty());
+    assert_eq!(Value::Empty, value);
 }
 
 #[test]
 fn r#if_else() {
-    let value = eval("if(true, 1, 2)").unwrap();
+    let value = eval("if_else(true, 1, 2)").unwrap();
     assert_eq!(Value::Integer(1), value);
 
-    let value = eval("if(false, 1, 2)").unwrap();
+    let value = eval("if_else(false, 1, 2)").unwrap();
     assert_eq!(Value::Integer(2), value);
 
-    let value = eval("if(true, '1', '2')").unwrap();
+    let value = eval("if_else(true, '1', '2')").unwrap();
     assert_eq!(Value::Integer(1), value);
 
-    let value = eval("if(false, '1', '2')").unwrap();
+    let value = eval("if_else(false, '1', '2')").unwrap();
     assert_eq!(Value::Integer(2), value);
 }