sam: Divide by float 0 returns +/-Inf

book/src/command/super.md

@@ -500,18 +500,18 @@ or trying to debug a halted query with a vague error message.
 
 For example, this query
 ```mdtest-command
-echo '1 2 0 3' | super -s -c '10.0/this' -
+echo '1 2 0 5' | super -s -c '10/this' -
 ```
 produces
 ```mdtest-output
-10.
-5.
+10
+5
 error("divide by zero")
-3.3333333333333335
+2
 ```
 and
 ```mdtest-command
-echo '1 2 0 3' | super -c '10.0/this' - | super -s -c 'is_error(this)' -
+echo '1 2 0 5' | super -c '10/this' - | super -s -c 'is_error(this)' -
 ```
 produces just
 ```mdtest-output

runtime/sam/expr/eval.go

@@ -522,11 +522,7 @@ func (d *Divide) Eval(this super.Value) super.Value {
 		}
 		return super.NewInt(typ, toInt(lhsVal)/v)
 	case super.IsFloat(id):
-		v := toFloat(rhsVal)
-		if v == 0 {
-			return d.sctx.NewError(DivideByZero)
-		}
-		return super.NewFloat(typ, toFloat(lhsVal)/v)
+		return super.NewFloat(typ, toFloat(lhsVal)/toFloat(rhsVal))
 	}
 	return d.sctx.NewErrorf("type %s incompatible with '/' operator", sup.FormatType(typ))
 }

runtime/ztests/expr/arith-divide-by-zero.yaml

@@ -6,6 +6,8 @@ input: |
   {a:null::uint64,b:0::uint64}
   {a:2::uint64,b:null::uint64}
   {a:5::uint64,b:0::uint64}
+  {a:1.,b:0.}
+  {a:-1.,b:0.}
 
 output: |
   null::uint64
@@ -14,3 +16,7 @@ output: |
   null::uint64
   error("divide by zero")
   error("divide by zero")
+  +Inf
+  error("type float64 incompatible with '%' operator")
+  -Inf
+  error("type float64 incompatible with '%' operator")