strips/pork
2
0
Fork 0
mirror of https://github.com/GayPizzaSpecifications/pork.git synced 2025-08-02 12:50:55 +00:00
Code Issues Packages Projects Releases Wiki Activity

evaluator: prevent double lookup when looking up value in a scope

Browse Source
This commit is contained in:
Alex Zenla 2023-09-05 01:09:26 -07:00
parent 7de8f8cd63
commit cc23789203
Signed by: alex
GPG Key ID: C0780728420EBFE5
1 changed files with 17 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
evaluator/src/main/kotlin/gay/pizza/pork/evaluator/Scope.kt
View File

@ -4,11 +4,6 @@ class Scope(val parent: Scope? = null, inherits: List<Scope> = emptyList()) {
private val inherited = inherits.toMutableList()
private val variables = mutableMapOf<String, Any>()
fun has(name: String): Boolean =
variables.containsKey(name) ||
(parent?.has(name) ?: false) ||
inherited.any { inherit -> inherit.has(name) }
fun define(name: String, value: Any) {
if (variables.containsKey(name)) {
throw RuntimeException("Variable '${name}' is already defined")
@ -17,20 +12,30 @@ class Scope(val parent: Scope? = null, inherits: List<Scope> = emptyList()) {
}
fun value(name: String): Any {
val value = valueOrNotFound(name)
if (value == NotFound) {
throw RuntimeException("Variable '${name}' not defined.")
}
return value
}
private fun valueOrNotFound(name: String): Any {
val value = variables[name]
if (value == null) {
if (parent != null) {
if (parent.has(name)) {
return parent.value(name)
val parentMaybeFound = parent.valueOrNotFound(name)
if (parentMaybeFound != NotFound) {
return parentMaybeFound
}
}
for (inherit in inherited) {
if (inherit.has(name)) {
return inherit.value(name)
val inheritMaybeFound = inherit.valueOrNotFound(name)
if (inheritMaybeFound != NotFound) {
return inheritMaybeFound
}
}
throw RuntimeException("Variable '${name}' not defined.")
return NotFound
}
return value
}
@ -57,4 +62,6 @@ class Scope(val parent: Scope? = null, inherits: List<Scope> = emptyList()) {
internal fun inherit(scope: Scope) {
inherited.add(scope)
}
private object NotFound
}