Merge all visit() implementations into a single module.
Avoids template instantiation conflicts introduced by adding the second visit() in taggedalgebraic.taggedalgebraic. A compatibility alias is left in the taggedunion module to avoid breaking backwards compatibility.
This commit is contained in:
Sönke Ludwig
parent
44a2b970af
commit
8f425b37b5
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@ -691,7 +691,9 @@ unittest {
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*/
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ref inout(T) get(T, U)(ref inout(TaggedAlgebraic!U) ta)
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{
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return ta.m_union.value!T;
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static if (is(T == TaggedUnion!U))
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return ta.m_union;
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else return ta.m_union.value!T;
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}
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/// ditto
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inout(T) get(T, U)(inout(TaggedAlgebraic!U) ta)
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@ -798,86 +800,6 @@ unittest {
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});
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}
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/** Forwards visit functionality from taggedunion.
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A visitor can have one of three forms:
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$(UL
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$(LI function or delegate taking a single typed parameter)
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$(LI function or delegate taking no parameters)
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$(LI function or delegate template taking any single parameter)
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)
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....
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*/
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template visit(VISITORS...)
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if (VISITORS.length > 0)
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{
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auto visit(U)(auto ref TaggedAlgebraic!U ta)
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{
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return taggedalgebraic.taggedunion.visit!VISITORS(ta.m_union);
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}
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}
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unittest {
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// repeat test from TaggedUnion
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union U {
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Void none;
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int count;
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float length;
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}
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TaggedAlgebraic!U u;
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//
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static assert(is(typeof(u.visit!((int) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((float) {}, (_) {}, () {}))));
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static assert(!is(typeof(u.visit!((_) {})))); // missing void handler
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static assert(!is(typeof(u.visit!(() {})))); // missing value handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (string) {})))); // invalid typed handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, () {})))); // duplicate void handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (_) {})))); // duplicate generic handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, (float) {}, () {})))); // duplicate typed handler
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// TODO: error out for superfluous generic handlers
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//static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, (_) {})))); // superfluous generic handler
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}
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/** Forwards tryVisit functionality from taggedunion.
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The same as `visit`, except that failure to handle types is checked at runtime.
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Instead of failing to compile, `tryVisit` will throw an `Exception` if none
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of the handlers is able to handle the value contained in `ta`.
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*/
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template tryVisit(VISITORS...)
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if (VISITORS.length > 0)
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{
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auto tryVisit(U)(auto ref TaggedAlgebraic!U ta)
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{
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return taggedalgebraic.taggedunion.tryVisit!VISITORS(ta.m_union);
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}
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}
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// repeat from TaggedUnion
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unittest {
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import std.exception : assertThrown;
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union U {
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int number;
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string text;
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}
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alias TA = TaggedAlgebraic!U;
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auto ta = TA(42);
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ta.tryVisit!((int n) { assert(n == 42); });
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assertThrown(ta.tryVisit!((string s) { assert(false); }));
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}
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/// User-defined attibute to disable `opIndex` forwarding for a particular tagged union member.
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@property auto disableIndex() { assert(__ctfe, "disableIndex must only be used as an attribute."); return DisableOpAttribute(OpKind.index, null); }
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@ -7,6 +7,10 @@
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*/
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module taggedalgebraic.taggedunion;
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// scheduled for deprecation
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static import taggedalgebraic.visit;
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alias visit = taggedalgebraic.visit.visit;
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import std.algorithm.mutation : move, swap;
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import std.meta;
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import std.range : isOutputRange;
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@ -512,215 +516,9 @@ unittest { // null members should be assignable
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assert(val.kind == val.Kind.Null);
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}
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/** Dispatches the value contained on a `TaggedUnion` to a set of visitors.
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A visitor can have one of three forms:
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$(UL
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$(LI function or delegate taking a single typed parameter)
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$(LI function or delegate taking no parameters)
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$(LI function or delegate template taking any single parameter)
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)
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....
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*/
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template visit(VISITORS...)
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if (VISITORS.length > 0)
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{
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auto visit(TU)(auto ref TU tu)
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if (isInstanceOf!(TaggedUnion, TU))
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{
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alias val = validateHandlers!(TU, VISITORS);
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final switch (tu.kind) {
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static foreach (k; EnumMembers!(TU.Kind)) {
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case k: {
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static if (isUnitType!(TU.FieldTypes[k]))
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alias T = void;
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else alias T = TU.FieldTypes[k];
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alias h = selectHandler!(T, VISITORS);
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static if (is(typeof(h) == typeof(null))) static assert(false, "No visitor defined for type type "~T.stringof);
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else static if (is(typeof(h) == string)) static assert(false, h);
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else static if (is(T == void)) return h();
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else return h(tu.value!k);
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}
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}
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}
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}
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}
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///
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unittest {
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static if (__VERSION__ >= 2081) {
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import std.conv : to;
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union U {
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int number;
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string text;
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}
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alias TU = TaggedUnion!U;
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auto tu = TU.number(42);
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tu.visit!(
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(int n) { assert(n == 42); },
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(string s) { assert(false); }
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);
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assert(tu.visit!((v) => to!int(v)) == 42);
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tu.setText("43");
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assert(tu.visit!((v) => to!int(v)) == 43);
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}
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}
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unittest {
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union U {
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Void none;
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int count;
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float length;
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}
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TaggedUnion!U u;
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//
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static assert(is(typeof(u.visit!((int) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((float) {}, (_) {}, () {}))));
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static assert(!is(typeof(u.visit!((_) {})))); // missing void handler
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static assert(!is(typeof(u.visit!(() {})))); // missing value handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (string) {})))); // invalid typed handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, () {})))); // duplicate void handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (_) {})))); // duplicate generic handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, (float) {}, () {})))); // duplicate typed handler
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// TODO: error out for superfluous generic handlers
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//static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, (_) {})))); // superfluous generic handler
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}
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/** The same as `visit`, except that failure to handle types is checked at runtime.
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Instead of failing to compile, `tryVisit` will throw an `Exception` if none
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of the handlers is able to handle the value contained in `tu`.
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*/
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template tryVisit(VISITORS...)
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if (VISITORS.length > 0)
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{
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auto tryVisit(TU)(auto ref TU tu)
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if (isInstanceOf!(TaggedUnion, TU))
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{
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final switch (tu.kind) {
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static foreach (k; EnumMembers!(TU.Kind)) {
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case k: {
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static if (isUnitType!(TU.FieldTypes[k]))
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alias T = void;
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else alias T = TU.FieldTypes[k];
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alias h = selectHandler!(T, VISITORS);
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static if (is(typeof(h) == typeof(null))) throw new Exception("Type "~T.stringof~" not handled by any visitor.");
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else static if (is(typeof(h) == string)) static assert(false, h);
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else static if (is(T == void)) return h();
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else return h(tu.value!k);
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}
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}
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}
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}
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}
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///
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unittest {
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import std.exception : assertThrown;
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union U {
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int number;
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string text;
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}
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alias TU = TaggedUnion!U;
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auto tu = TU.number(42);
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tu.tryVisit!((int n) { assert(n == 42); });
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assertThrown(tu.tryVisit!((string s) { assert(false); }));
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}
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enum isUnitType(T) = is(T == Void) || is(T == void) || is(T == typeof(null));
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private template validateHandlers(TU, VISITORS...)
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{
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import std.traits : isSomeFunction;
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alias Types = TU.FieldTypes;
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static foreach (int i; 0 .. VISITORS.length) {
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static assert(!is(VISITORS[i]) || isSomeFunction!(VISITORS[i]),
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"Visitor at index "~i.stringof~" must be a function/delegate literal: "~VISITORS[i].stringof);
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static assert(anySatisfy!(matchesType!(VISITORS[i]), Types),
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"Visitor at index "~i.stringof~" does not match any type of "~TU.FieldTypes.stringof);
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}
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}
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private template matchesType(alias fun) {
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import std.traits : ParameterTypeTuple, isSomeFunction;
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template matchesType(T) {
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static if (isSomeFunction!fun) {
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alias Params = ParameterTypeTuple!fun;
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static if (Params.length == 0 && isUnitType!T) enum matchesType = true;
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else static if (Params.length == 1 && is(T == Params[0])) enum matchesType = true;
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else enum matchesType = false;
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} else static if (!isUnitType!T) {
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static if (isSomeFunction!(fun!T)) {
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alias Params = ParameterTypeTuple!(fun!T);
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static if (Params.length == 1 && is(T == Params[0])) enum matchesType = true;
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else enum matchesType = false;
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} else enum matchesType = false;
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} else enum matchesType = false;
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}
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}
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private template selectHandler(T, VISITORS...)
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{
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import std.traits : ParameterTypeTuple, isSomeFunction;
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template typedIndex(int i, int matched_index = -1) {
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static if (i < VISITORS.length) {
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alias fun = VISITORS[i];
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static if (isSomeFunction!fun) {
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alias Params = ParameterTypeTuple!fun;
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static if (Params.length > 1) enum typedIndex = "Visitor at index "~i.stringof~" must not take more than one parameter.";
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else static if (Params.length == 0 && is(T == void) || Params.length == 1 && is(T == Params[0])) {
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static if (matched_index >= 0) enum typedIndex = "Vistor at index "~i.stringof~" conflicts with visitor at index "~matched_index~".";
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else enum typedIndex = typedIndex!(i+1, i);
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} else enum typedIndex = typedIndex!(i+1, matched_index);
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} else enum typedIndex = typedIndex!(i+1, matched_index);
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} else enum typedIndex = matched_index;
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}
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template genericIndex(int i, int matched_index = -1) {
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static if (i < VISITORS.length) {
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alias fun = VISITORS[i];
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static if (!isSomeFunction!fun) {
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static if (isSomeFunction!(fun!T)) {
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static if (ParameterTypeTuple!(fun!T).length == 1) {
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static if (matched_index >= 0) enum genericIndex = "Only one generic visitor allowed";
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else enum genericIndex = genericIndex!(i+1, i);
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} else enum genericIndex = "Generic visitor at index "~i.stringof~" must have a single parameter.";
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} else enum genericIndex = "Visitor at index "~i.stringof~" (or its template instantiation with type "~T.stringof~") must be a valid function or delegate.";
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} else enum genericIndex = genericIndex!(i+1, matched_index);
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} else enum genericIndex = matched_index;
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}
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enum typed_index = typedIndex!0;
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static if (is(T == void)) enum generic_index = -1;
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else enum generic_index = genericIndex!0;
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static if (is(typeof(typed_index) == string)) enum selectHandler = typed_index;
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else static if (is(typeof(generic_index == string))) enum selectHandler = generic_index;
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else static if (typed_index >= 0) alias selectHandler = VISITORS[typed_index];
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else static if (generic_index >= 0) alias selectHandler = VISITORS[generic_index];
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else enum selectHandler = null;
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}
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private string pascalCase(string camel_case)
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{
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270
source/taggedalgebraic/visit.d
Normal file
270
source/taggedalgebraic/visit.d
Normal file
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@ -0,0 +1,270 @@
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module taggedalgebraic.visit;
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import taggedalgebraic.taggedalgebraic;
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import taggedalgebraic.taggedunion;
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import std.meta : anySatisfy;
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import std.traits : EnumMembers, isInstanceOf;
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/** Dispatches the value contained on a `TaggedUnion` or `TaggedAlgebraic` to a
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set of visitors.
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A visitor can have one of three forms:
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$(UL
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$(LI function or delegate taking a single typed parameter)
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$(LI function or delegate taking no parameters)
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$(LI function or delegate template taking any single parameter)
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)
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....
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*/
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template visit(VISITORS...)
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if (VISITORS.length > 0)
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{
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auto visit(TU)(auto ref TU tu)
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if (isInstanceOf!(TaggedUnion, TU))
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{
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alias val = validateHandlers!(TU, VISITORS);
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final switch (tu.kind) {
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static foreach (k; EnumMembers!(TU.Kind)) {
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case k: {
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static if (isUnitType!(TU.FieldTypes[k]))
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alias T = void;
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else alias T = TU.FieldTypes[k];
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alias h = selectHandler!(T, VISITORS);
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static if (is(typeof(h) == typeof(null))) static assert(false, "No visitor defined for type type "~T.stringof);
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else static if (is(typeof(h) == string)) static assert(false, h);
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else static if (is(T == void)) return h();
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else return h(tu.value!k);
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}
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}
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}
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}
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auto visit(U)(auto ref TaggedAlgebraic!U ta)
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{
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return visit(ta.get!(TaggedUnion!U));
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}
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}
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///
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unittest {
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static if (__VERSION__ >= 2081) {
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import std.conv : to;
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union U {
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int number;
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string text;
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}
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alias TU = TaggedUnion!U;
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auto tu = TU.number(42);
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tu.visit!(
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(int n) { assert(n == 42); },
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(string s) { assert(false); }
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);
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assert(tu.visit!((v) => to!int(v)) == 42);
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tu.setText("43");
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assert(tu.visit!((v) => to!int(v)) == 43);
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}
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}
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unittest {
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// repeat test from TaggedUnion
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union U {
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Void none;
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int count;
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float length;
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}
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TaggedAlgebraic!U u;
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//
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static assert(is(typeof(u.visit!((int) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((float) {}, (_) {}, () {}))));
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static assert(!is(typeof(u.visit!((_) {})))); // missing void handler
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static assert(!is(typeof(u.visit!(() {})))); // missing value handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (string) {})))); // invalid typed handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, () {})))); // duplicate void handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (_) {})))); // duplicate generic handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, (float) {}, () {})))); // duplicate typed handler
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// TODO: error out for superfluous generic handlers
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//static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, (_) {})))); // superfluous generic handler
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}
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unittest {
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union U {
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Void none;
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int count;
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float length;
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}
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TaggedUnion!U u;
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//
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static assert(is(typeof(u.visit!((int) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, () {}))));
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static assert(is(typeof(u.visit!((_) {}, (float) {}, () {}))));
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static assert(is(typeof(u.visit!((float) {}, (_) {}, () {}))));
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static assert(!is(typeof(u.visit!((_) {})))); // missing void handler
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static assert(!is(typeof(u.visit!(() {})))); // missing value handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (string) {})))); // invalid typed handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, () {})))); // duplicate void handler
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static assert(!is(typeof(u.visit!((_) {}, () {}, (_) {})))); // duplicate generic handler
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static assert(!is(typeof(u.visit!((int) {}, (float) {}, (float) {}, () {})))); // duplicate typed handler
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// TODO: error out for superfluous generic handlers
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//static assert(!is(typeof(u.visit!((int) {}, (float) {}, () {}, (_) {})))); // superfluous generic handler
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}
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/** The same as `visit`, except that failure to handle types is checked at runtime.
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|
||||
Instead of failing to compile, `tryVisit` will throw an `Exception` if none
|
||||
of the handlers is able to handle the value contained in `tu`.
|
||||
*/
|
||||
template tryVisit(VISITORS...)
|
||||
if (VISITORS.length > 0)
|
||||
{
|
||||
auto tryVisit(TU)(auto ref TU tu)
|
||||
if (isInstanceOf!(TaggedUnion, TU))
|
||||
{
|
||||
final switch (tu.kind) {
|
||||
static foreach (k; EnumMembers!(TU.Kind)) {
|
||||
case k: {
|
||||
static if (isUnitType!(TU.FieldTypes[k]))
|
||||
alias T = void;
|
||||
else alias T = TU.FieldTypes[k];
|
||||
alias h = selectHandler!(T, VISITORS);
|
||||
static if (is(typeof(h) == typeof(null))) throw new Exception("Type "~T.stringof~" not handled by any visitor.");
|
||||
else static if (is(typeof(h) == string)) static assert(false, h);
|
||||
else static if (is(T == void)) return h();
|
||||
else return h(tu.value!k);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
auto tryVisit(U)(auto ref TaggedAlgebraic!U ta)
|
||||
{
|
||||
return tryVisit(ta.get!(TaggedUnion!U));
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
unittest {
|
||||
import std.exception : assertThrown;
|
||||
|
||||
union U {
|
||||
int number;
|
||||
string text;
|
||||
}
|
||||
alias TU = TaggedUnion!U;
|
||||
|
||||
auto tu = TU.number(42);
|
||||
tu.tryVisit!((int n) { assert(n == 42); });
|
||||
assertThrown(tu.tryVisit!((string s) { assert(false); }));
|
||||
}
|
||||
|
||||
// repeat from TaggedUnion
|
||||
unittest {
|
||||
import std.exception : assertThrown;
|
||||
|
||||
union U {
|
||||
int number;
|
||||
string text;
|
||||
}
|
||||
alias TA = TaggedAlgebraic!U;
|
||||
|
||||
auto ta = TA(42);
|
||||
ta.tryVisit!((int n) { assert(n == 42); });
|
||||
assertThrown(ta.tryVisit!((string s) { assert(false); }));
|
||||
}
|
||||
|
||||
|
||||
private template validateHandlers(TU, VISITORS...)
|
||||
{
|
||||
import std.traits : isSomeFunction;
|
||||
|
||||
alias Types = TU.FieldTypes;
|
||||
|
||||
static foreach (int i; 0 .. VISITORS.length) {
|
||||
static assert(!is(VISITORS[i]) || isSomeFunction!(VISITORS[i]),
|
||||
"Visitor at index "~i.stringof~" must be a function/delegate literal: "~VISITORS[i].stringof);
|
||||
static assert(anySatisfy!(matchesType!(VISITORS[i]), Types),
|
||||
"Visitor at index "~i.stringof~" does not match any type of "~TU.FieldTypes.stringof);
|
||||
}
|
||||
}
|
||||
|
||||
private template matchesType(alias fun) {
|
||||
import std.traits : ParameterTypeTuple, isSomeFunction;
|
||||
|
||||
template matchesType(T) {
|
||||
static if (isSomeFunction!fun) {
|
||||
alias Params = ParameterTypeTuple!fun;
|
||||
static if (Params.length == 0 && isUnitType!T) enum matchesType = true;
|
||||
else static if (Params.length == 1 && is(T == Params[0])) enum matchesType = true;
|
||||
else enum matchesType = false;
|
||||
} else static if (!isUnitType!T) {
|
||||
static if (isSomeFunction!(fun!T)) {
|
||||
alias Params = ParameterTypeTuple!(fun!T);
|
||||
static if (Params.length == 1 && is(T == Params[0])) enum matchesType = true;
|
||||
else enum matchesType = false;
|
||||
} else enum matchesType = false;
|
||||
} else enum matchesType = false;
|
||||
}
|
||||
}
|
||||
|
||||
private template selectHandler(T, VISITORS...)
|
||||
{
|
||||
import std.traits : ParameterTypeTuple, isSomeFunction;
|
||||
|
||||
template typedIndex(int i, int matched_index = -1) {
|
||||
static if (i < VISITORS.length) {
|
||||
alias fun = VISITORS[i];
|
||||
static if (isSomeFunction!fun) {
|
||||
alias Params = ParameterTypeTuple!fun;
|
||||
static if (Params.length > 1) enum typedIndex = "Visitor at index "~i.stringof~" must not take more than one parameter.";
|
||||
else static if (Params.length == 0 && is(T == void) || Params.length == 1 && is(T == Params[0])) {
|
||||
static if (matched_index >= 0) enum typedIndex = "Vistor at index "~i.stringof~" conflicts with visitor at index "~matched_index~".";
|
||||
else enum typedIndex = typedIndex!(i+1, i);
|
||||
} else enum typedIndex = typedIndex!(i+1, matched_index);
|
||||
} else enum typedIndex = typedIndex!(i+1, matched_index);
|
||||
} else enum typedIndex = matched_index;
|
||||
}
|
||||
|
||||
template genericIndex(int i, int matched_index = -1) {
|
||||
static if (i < VISITORS.length) {
|
||||
alias fun = VISITORS[i];
|
||||
static if (!isSomeFunction!fun) {
|
||||
static if (isSomeFunction!(fun!T)) {
|
||||
static if (ParameterTypeTuple!(fun!T).length == 1) {
|
||||
static if (matched_index >= 0) enum genericIndex = "Only one generic visitor allowed";
|
||||
else enum genericIndex = genericIndex!(i+1, i);
|
||||
} else enum genericIndex = "Generic visitor at index "~i.stringof~" must have a single parameter.";
|
||||
} else enum genericIndex = "Visitor at index "~i.stringof~" (or its template instantiation with type "~T.stringof~") must be a valid function or delegate.";
|
||||
} else enum genericIndex = genericIndex!(i+1, matched_index);
|
||||
} else enum genericIndex = matched_index;
|
||||
}
|
||||
|
||||
enum typed_index = typedIndex!0;
|
||||
static if (is(T == void)) enum generic_index = -1;
|
||||
else enum generic_index = genericIndex!0;
|
||||
|
||||
static if (is(typeof(typed_index) == string)) enum selectHandler = typed_index;
|
||||
else static if (is(typeof(generic_index == string))) enum selectHandler = generic_index;
|
||||
else static if (typed_index >= 0) alias selectHandler = VISITORS[typed_index];
|
||||
else static if (generic_index >= 0) alias selectHandler = VISITORS[generic_index];
|
||||
else enum selectHandler = null;
|
||||
}
|
||||
Loading…
Reference in a new issue