lang: core, funcs, types: Add ctx to simple func

Plumb through the standard context.Context so that a function can be
cancelled if someone requests this. It makes it less awkward to write
simple functions that might depend on io or network access.

lang/core/math/fortytwo_func.go

@@ -30,6 +30,7 @@
 package coremath
 
 import (
+	"context"
 	"fmt"
 
 	"github.com/purpleidea/mgmt/lang/funcs/simplepoly"
@@ -57,8 +58,8 @@ func init() {
 // in a sig field, like how we demonstrate in the implementation of FortyTwo. If
 // the API doesn't change, then this is an example of how to build this as a
 // wrapper.
-func fortyTwo(sig *types.Type) func([]types.Value) (types.Value, error) {
-	return func(input []types.Value) (types.Value, error) {
+func fortyTwo(sig *types.Type) func(context.Context, []types.Value) (types.Value, error) {
+	return func(ctx context.Context, input []types.Value) (types.Value, error) {
 		return FortyTwo(sig, input)
 	}
 }

lang/core/math/minus1_func.go

@@ -30,6 +30,8 @@
 package coremath
 
 import (
+	"context"
+
 	"github.com/purpleidea/mgmt/lang/funcs/simple"
 	"github.com/purpleidea/mgmt/lang/types"
 )
@@ -42,7 +44,7 @@ func init() {
 }
 
 // Minus1 takes an int and subtracts one from it.
-func Minus1(input []types.Value) (types.Value, error) {
+func Minus1(ctx context.Context, input []types.Value) (types.Value, error) {
 	// TODO: check for overflow
 	return &types.IntValue{
 		V: input[0].Int() - 1,

lang/core/math/mod_func.go

@@ -30,6 +30,7 @@
 package coremath
 
 import (
+	"context"
 	"fmt"
 	"math"
 
@@ -54,7 +55,7 @@ func init() {
 // both of KindInt or both of KindFloat, and it will return the same kind. If
 // you pass in a divisor of zero, this will error, eg: mod(x, 0) = NaN.
 // TODO: consider returning zero instead of erroring?
-func Mod(input []types.Value) (types.Value, error) {
+func Mod(ctx context.Context, input []types.Value) (types.Value, error) {
 	var x, y float64
 	var float bool
 	k := input[0].Type().Kind

lang/core/math/pow_func.go

@@ -30,6 +30,7 @@
 package coremath
 
 import (
+	"context"
 	"fmt"
 	"math"
 
@@ -45,7 +46,7 @@ func init() {
 }
 
 // Pow returns x ^ y, the base-x exponential of y.
-func Pow(input []types.Value) (types.Value, error) {
+func Pow(ctx context.Context, input []types.Value) (types.Value, error) {
 	x, y := input[0].Float(), input[1].Float()
 	// FIXME: check for overflow
 	z := math.Pow(x, y)

lang/core/math/sqrt_func.go

@@ -30,6 +30,7 @@
 package coremath
 
 import (
+	"context"
 	"fmt"
 	"math"
 
@@ -45,7 +46,7 @@ func init() {
 }
 
 // Sqrt returns sqrt(x), the square root of x.
-func Sqrt(input []types.Value) (types.Value, error) {
+func Sqrt(ctx context.Context, input []types.Value) (types.Value, error) {
 	x := input[0].Float()
 	y := math.Sqrt(x)
 	if math.IsNaN(y) {

lang/core/math/sqrt_func_test.go

@@ -30,6 +30,7 @@
 package coremath
 
 import (
+	"context"
 	"fmt"
 	"math"
 	"testing"
@@ -40,7 +41,7 @@ import (
 func testSqrtSuccess(input, sqrt float64) error {
 	inputVal := &types.FloatValue{V: input}
 
-	val, err := Sqrt([]types.Value{inputVal})
+	val, err := Sqrt(context.Background(), []types.Value{inputVal})
 	if err != nil {
 		return err
 	}
@@ -52,7 +53,7 @@ func testSqrtSuccess(input, sqrt float64) error {
 
 func testSqrtError(input float64) error {
 	inputVal := &types.FloatValue{V: input}
-	_, err := Sqrt([]types.Value{inputVal})
+	_, err := Sqrt(context.Background(), []types.Value{inputVal})
 	if err == nil {
 		return fmt.Errorf("expected error for input %f, got nil", input)
 	}