You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
100 lines
2.7 KiB
Go
100 lines
2.7 KiB
Go
package cty
|
|
|
|
import (
|
|
"fmt"
|
|
)
|
|
|
|
// anyUnknown is a helper to easily check if a set of values contains any
|
|
// unknowns, for operations that short-circuit to return unknown in that case.
|
|
func anyUnknown(values ...Value) bool {
|
|
for _, val := range values {
|
|
if val.v == unknown {
|
|
return true
|
|
}
|
|
}
|
|
return false
|
|
}
|
|
|
|
// typeCheck tests whether all of the given values belong to the given type.
|
|
// If the given types are a mixture of the given type and the dynamic
|
|
// pseudo-type then a short-circuit dynamic value is returned. If the given
|
|
// values are all of the correct type but at least one is unknown then
|
|
// a short-circuit unknown value is returned. If any other types appear then
|
|
// an error is returned. Otherwise (finally!) the result is nil, nil.
|
|
func typeCheck(required Type, ret Type, values ...Value) (shortCircuit *Value, err error) {
|
|
hasDynamic := false
|
|
hasUnknown := false
|
|
|
|
for i, val := range values {
|
|
if val.ty == DynamicPseudoType {
|
|
hasDynamic = true
|
|
continue
|
|
}
|
|
|
|
if !val.Type().Equals(required) {
|
|
return nil, fmt.Errorf(
|
|
"type mismatch: want %s but value %d is %s",
|
|
required.FriendlyName(),
|
|
i, val.ty.FriendlyName(),
|
|
)
|
|
}
|
|
|
|
if val.v == unknown {
|
|
hasUnknown = true
|
|
}
|
|
}
|
|
|
|
if hasDynamic {
|
|
return &DynamicVal, nil
|
|
}
|
|
|
|
if hasUnknown {
|
|
ret := UnknownVal(ret)
|
|
return &ret, nil
|
|
}
|
|
|
|
return nil, nil
|
|
}
|
|
|
|
// mustTypeCheck is a wrapper around typeCheck that immediately panics if
|
|
// any error is returned.
|
|
func mustTypeCheck(required Type, ret Type, values ...Value) *Value {
|
|
shortCircuit, err := typeCheck(required, ret, values...)
|
|
if err != nil {
|
|
panic(err)
|
|
}
|
|
return shortCircuit
|
|
}
|
|
|
|
// shortCircuitForceType takes the return value from mustTypeCheck and
|
|
// replaces it with an unknown of the given type if the original value was
|
|
// DynamicVal.
|
|
//
|
|
// This is useful for operations that are specified to always return a
|
|
// particular type, since then a dynamic result can safely be "upgrade" to
|
|
// a strongly-typed unknown, which then allows subsequent operations to
|
|
// be actually type-checked.
|
|
//
|
|
// It is safe to use this only if the operation in question is defined as
|
|
// returning either a value of the given type or panicking, since we know
|
|
// then that subsequent operations won't run if the operation panics.
|
|
//
|
|
// If the given short-circuit value is *not* DynamicVal then it must be
|
|
// of the given type, or this function will panic.
|
|
func forceShortCircuitType(shortCircuit *Value, ty Type) *Value {
|
|
if shortCircuit == nil {
|
|
return nil
|
|
}
|
|
|
|
if shortCircuit.ty == DynamicPseudoType {
|
|
ret := UnknownVal(ty)
|
|
return &ret
|
|
}
|
|
|
|
if !shortCircuit.ty.Equals(ty) {
|
|
panic("forceShortCircuitType got value of wrong type")
|
|
}
|
|
|
|
return shortCircuit
|
|
}
|