Merge #55

55: More comparisons r=vext01 a=ltratt

This PR adds more comparisons to yksom: reference equality (1dca2bc) and various comparisons for doubles (82d35c5). Notice that the former commit means that we diverge slightly from SOM's current semantics (see SOM-st/SOM#23) although I think it's fair to say that @smarr thinks the approach we're taking in this PR is the right one (and if I've got that wrong, hopefully he'll shout!).

Co-authored-by: Laurence Tratt <[email protected]>

lang_tests/double10.som

@@ -0,0 +1,46 @@
+"
+VM:
+  status: success
+  stdout:
+    false
+    true
+    true
+    true
+    false
+    true
+    false
+    false
+    false
+    true
+    true
+    false
+    true
+    true
+    true
+    false
+"
+
+double10 = (
+    run = (
+        (1.0 = 0) println.
+        (1.0 = 1) println.
+        (1.0 ~= 0) println.
+        (1.0 ~= 1) println.
+
+        (1.0 < 1) println.
+        (1.0 < 2) println.
+        (2.0 < 0) println.
+
+        (1.0 > 1) println.
+        (1.0 > 2) println.
+        (2.0 > 0) println.
+
+        (1.0 >= 1) println.
+        (1.0 >= 2) println.
+        (2.0 >= 0) println.
+
+        (1.0 <= 1) println.
+        (1.0 <= 2) println.
+        (2.0 <= 0) println.
+    )
+)

lang_tests/obj1.som

@@ -0,0 +1,29 @@
+"
+VM:
+  status: success
+  stdout:
+    true
+    false
+    false
+    true
+    true
+    true
+    false
+    false
+    true
+"
+
+obj1 = (
+    run = (
+        (1 == 1) println.
+        (1 <> 1) println.
+        (1 ~= 1) println.
+        (1 <> 2) println.
+        (1 ~= 2) println.
+
+        (self == self) println.
+        (self <> self) println.
+        (self == 'a') println.
+        (self <> 'a') println.
+    )
+)

lang_tests/obj2.som

@@ -0,0 +1,22 @@
+"
+VM:
+  status: success
+  stdout:
+    true
+    true
+    true
+    true
+    false
+    false
+"
+
+obj2 = (
+    run = (
+        (1 == 1) println.
+        (100 == 100) println.
+        ((1 << 200) == (1 << 200)) println.
+        (1.0 == 1.0) println.
+        (1.0 == 1) println.
+        (1 == 1.0) println.
+    )
+)

lib/SOM/Double.som

@@ -4,5 +4,9 @@ Double = (
     * argument = primitive
     =  argument = primitive
     <  argument = primitive
+    >  argument = ( ^(self >= argument) and: [ self <> argument ] )
+    >= argument = ( ^(self < argument) not )
+    <= argument = ( ^(self < argument) or: [ self = argument ] )
+    negative = ( ^self < 0.0 )
     asString = primitive
 )

lib/SOM/False.som

@@ -1,6 +1,8 @@
 False = Boolean (
     asString = ( ^'false' )
     not = ( ^true )
+    or: block = ( ^block value )
+    and: block = ( ^false )
     ifTrue: block = ( ^nil )
     ifFalse: block = ( ^block value )
 )

lib/SOM/Object.som

@@ -2,6 +2,11 @@ Object = nil (
     class = primitive
     asString  = ( ^'instance of ' concatenate: (self class asString) )
 
+    =  other = ( ^self == other )
+    <> argument = ( ^(self = argument) not )
+    == other = primitive
+    ~= other = (^ (self == other) not )
+
     print = ( self asString print )
     println = (
         self print.

lib/SOM/True.som

@@ -1,6 +1,8 @@
 True = Boolean (
     asString = ( ^'true' )
     not = ( ^false )
+    or: block = ( ^true )
+    and: block = ( ^block value )
     ifTrue: block = ( ^block value )
     ifFalse: block = ( ^nil )
 )

src/lib/compiler/ast_to_instrs.rs

@@ -204,6 +204,10 @@ impl<'a> Compiler<'a> {
                     requires_args(1)?;
                     Ok(cobjects::MethodBody::Primitive(Primitive::Equals))
                 }
+                "==" => {
+                    requires_args(1)?;
+                    Ok(cobjects::MethodBody::Primitive(Primitive::RefEquals))
+                }
                 "~=" => {
                     requires_args(1)?;
                     Ok(cobjects::MethodBody::Primitive(Primitive::NotEquals))

src/lib/compiler/instrs.rs

@@ -49,6 +49,7 @@ pub enum Primitive {
     New,
     PrintNewline,
     PrintString,
+    RefEquals,
     Restart,
     Shl,
     Sub,

src/lib/vm/core.rs

@@ -440,6 +440,10 @@ impl VM {
                 self.stack_push(stry!(rcv.not_equals(self, self.stack_pop())));
                 SendReturn::Val
             }
+            Primitive::RefEquals => {
+                self.stack_push(stry!(rcv.ref_equals(self, self.stack_pop())));
+                SendReturn::Val
+            }
             Primitive::Restart => unreachable!(),
             Primitive::PrintNewline => {
                 println!();

src/lib/vm/objects/double.rs

@@ -90,6 +90,51 @@ impl Obj for Double {
             }))
         }
     }
+
+    fn ref_equals(&self, vm: &VM, other: Val) -> Result<Val, Box<VMError>> {
+        let b = if let Some(rhs) = other.try_downcast::<Double>(vm) {
+            self.val == rhs.double()
+        } else {
+            false
+        };
+        Ok(Val::from_bool(vm, b))
+    }
+
+    fn equals(&self, vm: &VM, other: Val) -> Result<Val, Box<VMError>> {
+        let b = if let Some(rhs) = other.as_isize(vm) {
+            self.val == (rhs as f64)
+        } else if let Some(rhs) = other.try_downcast::<Double>(vm) {
+            self.val == rhs.double()
+        } else if let Some(rhs) = other.try_downcast::<ArbInt>(vm) {
+            match rhs.bigint().to_f64() {
+                Some(i) => self.val == i,
+                None => false,
+            }
+        } else {
+            false
+        };
+
+        Ok(Val::from_bool(vm, b))
+    }
+
+    fn less_than(&self, vm: &VM, other: Val) -> Result<Val, Box<VMError>> {
+        let b = if let Some(rhs) = other.as_isize(vm) {
+            self.val < (rhs as f64)
+        } else if let Some(rhs) = other.try_downcast::<Double>(vm) {
+            self.val < rhs.double()
+        } else if let Some(rhs) = other.try_downcast::<ArbInt>(vm) {
+            match rhs.bigint().to_f64() {
+                Some(i) => self.val < i,
+                None => false,
+            }
+        } else {
+            return Err(Box::new(VMError::NotANumber {
+                got: other.dyn_objtype(vm),
+            }));
+        };
+
+        Ok(Val::from_bool(vm, b))
+    }
 }
 
 impl StaticObjType for Double {

src/lib/vm/objects/integers.rs

@@ -142,6 +142,15 @@ impl Obj for ArbInt {
         }
     }
 
+    fn ref_equals(&self, vm: &VM, other: Val) -> Result<Val, Box<VMError>> {
+        let b = if let Some(rhs) = other.try_downcast::<ArbInt>(vm) {
+            self.val == rhs.val
+        } else {
+            false
+        };
+        Ok(Val::from_bool(vm, b))
+    }
+
     fn equals(&self, vm: &VM, other: Val) -> Result<Val, Box<VMError>> {
         let b = if other.dyn_objtype(vm) == ObjType::Int {
             debug_assert!(self.val != BigInt::from_isize(other.as_isize(vm).unwrap()).unwrap());

src/lib/vm/objects/mod.rs

@@ -105,6 +105,18 @@ pub trait Obj: std::fmt::Debug + abgc::GcLayout {
         unimplemented!();
     }
 
+    /// Is this `Val` reference equality equal to `other`? Only number types are likely to want to
+    /// override this.
+    fn ref_equals(&self, vm: &VM, other: Val) -> Result<Val, Box<VMError>> {
+        let other_tobj = other.tobj(vm)?;
+        let other_data =
+            unsafe { std::mem::transmute::<&dyn Obj, (*const u8, usize)>(&**other_tobj).0 };
+        Ok(Val::from_bool(
+            vm,
+            (self as *const _ as *const u8) == other_data,
+        ))
+    }
+
     /// Does this `Val` equal `other`?
     fn equals(&self, _: &VM, _: Val) -> Result<Val, Box<VMError>> {
         unimplemented!();

src/lib/vm/val.rs

@@ -411,6 +411,15 @@ impl Val {
             ValKind::GCBOX => self.tobj(vm).unwrap().to_strval(vm),
         }
     }
+
+    /// Is this `Val` reference equal to `other`? Notice that for integers (but not Doubles)
+    /// "reference equal" is equivalent to "equals".
+    pub fn ref_equals(&self, vm: &VM, other: Val) -> Result<Val, Box<VMError>> {
+        match self.valkind() {
+            ValKind::INT => self.equals(vm, other),
+            ValKind::GCBOX => self.tobj(vm)?.ref_equals(vm, other),
+        }
+    }
 }
 
 macro_rules! binop_all {