Add sqrt primitive.

Cargo.toml

@@ -38,6 +38,7 @@ itertools = "0.8"
 lrlex = "0.4"
 lrpar = "0.4"
 num-bigint = "0.2"
+num-integer = "0.1"
 num_enum = "0.3"
 num-traits = "0.2"
 natrob = { git="https://github.com/softdevteam/natrob", features=["abgc"] }

lang_tests/double12.som

@@ -0,0 +1,14 @@
+"
+VM:
+  status: success
+  stdout:
+    1.1
+    NaN
+"
+
+double12 = (
+    run = (
+        (1.21 sqrt) println.
+        (-1.1 sqrt) println.
+    )
+)

lang_tests/int26.som

@@ -0,0 +1,16 @@
+"
+VM:
+  status: success
+  stdout:
+    5
+    1267650600228229401496703205376
+    1.7320508075688772
+"
+
+int26 = (
+    run = (
+        (25 sqrt) println.
+        ((1 << 200) sqrt) println.
+        (3 sqrt) println.
+    )
+)

lang_tests/int27.som

@@ -0,0 +1,11 @@
+"
+VM:
+  status: error
+  stderr: DomainError
+"
+
+int27 = (
+    run = (
+        -1 sqrt.
+    )
+)

lang_tests/int28.som

@@ -0,0 +1,11 @@
+"
+VM:
+  status: error
+  stderr: DomainError
+"
+
+int28 = (
+    run = (
+        (-1 << 200) sqrt.
+    )
+)

lang_tests/int29.som

@@ -0,0 +1,18 @@
+"
+VM:
+  status: success
+  stdout:
+    Integer
+    Integer
+    Double
+    Integer
+"
+
+int29 = (
+    run = (
+        (4 sqrt class) println.
+        ((1 << 200) sqrt class) println.
+        (3 sqrt class) println.
+        ((1 << 199) sqrt class) println.
+    )
+)

lib/SOM/Double.som

@@ -8,5 +8,6 @@ Double = (
     >= argument = ( ^(self < argument) not )
     <= argument = ( ^(self < argument) or: [ self = argument ] )
     negative = ( ^self < 0.0 )
+    sqrt     = primitive
     asString = primitive
 )

lib/SOM/Integer.som

@@ -11,6 +11,7 @@ Integer = (
     >= argument = primitive
     << argument = primitive
     bitXor: argument = primitive
+    sqrt        = primitive
     asString    = primitive
 
     to: limit do: block = (

src/lib/compiler/ast_to_instrs.rs

@@ -238,6 +238,7 @@ impl<'a> Compiler<'a> {
                     requires_args(1)?;
                     Ok(cobjects::MethodBody::Primitive(Primitive::BitXor))
                 }
+                "sqrt" => Ok(cobjects::MethodBody::Primitive(Primitive::Sqrt)),
                 "asString" => Ok(cobjects::MethodBody::Primitive(Primitive::AsString)),
                 "class" => Ok(cobjects::MethodBody::Primitive(Primitive::Class)),
                 "concatenate:" => Ok(cobjects::MethodBody::Primitive(Primitive::Concatenate)),

src/lib/compiler/instrs.rs

@@ -53,6 +53,7 @@ pub enum Primitive {
     RefEquals,
     Restart,
     Shl,
+    Sqrt,
     Sub,
     /// Is this `value` (0), `value:` (1), or `value:with:` (2)?
     Value(u8),

src/lib/vm/core.rs

@@ -41,6 +41,8 @@ pub enum VMError {
     /// A value which can't be represented in an `usize`.
     CantRepresentAsUsize,
     DivisionByZero,
+    /// A value which is mathematically undefined.
+    DomainError,
     /// The VM is trying to exit.
     Exit,
     /// Tried to perform a `Val::downcast` operation on a non-boxed `Val`. Note that `expected`
@@ -465,6 +467,10 @@ impl VM {
                 self.stack_push(stry!(rcv.shl(self, self.stack_pop())));
                 SendReturn::Val
             }
+            Primitive::Sqrt => {
+                self.stack_push(stry!(rcv.sqrt(self)));
+                SendReturn::Val
+            }
             Primitive::Sub => {
                 self.stack_push(stry!(rcv.sub(self, self.stack_pop())));
                 SendReturn::Val

src/lib/vm/objects/double.rs

@@ -91,6 +91,10 @@ impl Obj for Double {
         }
     }
 
+    fn sqrt(&self, vm: &VM) -> Result<Val, Box<VMError>> {
+        Ok(Double::new(vm, self.val.sqrt()))
+    }
+
     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()

src/lib/vm/objects/integers.rs

@@ -17,7 +17,7 @@ use std::convert::TryFrom;
 
 use abgc_derive::GcLayout;
 use num_bigint::BigInt;
-use num_traits::{FromPrimitive, ToPrimitive};
+use num_traits::{FromPrimitive, ToPrimitive, Zero};
 
 use crate::vm::{
     core::{VMError, VM},
@@ -155,6 +155,14 @@ impl Obj for ArbInt {
         }
     }
 
+    fn sqrt(&self, vm: &VM) -> Result<Val, Box<VMError>> {
+        if self.val < Zero::zero() {
+            Err(Box::new(VMError::DomainError))
+        } else {
+            ArbInt::new(vm, self.val.sqrt())
+        }
+    }
+
     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

src/lib/vm/objects/mod.rs

@@ -110,6 +110,11 @@ pub trait Obj: std::fmt::Debug + abgc::GcLayout {
         unimplemented!();
     }
 
+    /// Produces a new `Val` which is the square root of this.
+    fn sqrt(&self, _: &VM) -> Result<Val, Box<VMError>> {
+        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>> {

src/lib/vm/val.rs

@@ -420,6 +420,23 @@ impl Val {
         self.tobj(vm).unwrap().shl(vm, other)
     }
 
+    /// Produces a new `Val` which is the square root of this.
+    pub fn sqrt(&self, vm: &VM) -> Result<Val, Box<VMError>> {
+        if let Some(lhs) = self.as_isize(vm) {
+            if lhs < 0 {
+                return Err(Box::new(VMError::DomainError));
+            } else {
+                let result = (lhs as f64).sqrt();
+                if result.round() == result {
+                    return Val::from_isize(vm, result as isize);
+                } else {
+                    return Ok(Double::new(vm, result));
+                }
+            }
+        }
+        self.tobj(vm).unwrap().sqrt(vm)
+    }
+
     pub fn to_strval(&self, vm: &VM) -> Result<Val, Box<VMError>> {
         debug_assert!(!self.is_illegal());
         match self.valkind() {