feat: recursive pattern match (#5)

* dev: draft pattern matching

* fix: unexpected .e in eval

* fix: platform independent path for linker output

* fix: workaround for noCore import handling

* gg

* revert: expression change

* feat: pattern match on simple enum class

* feat: pattern match on sample class instance

* dev: match result

* dev: reorder syntax cons

* dev: pass all tests

* dev: simplify matchPat

* dev: start match building

* dev: refactor a bit

* dev: elementary value match

* dev: draft recursive match building

* dev: finish recursive match building

* dev: fix some recursion bugs

* dev: value coverage check

* dev: pass all samples

---------

Co-authored-by: seven-mile <[email protected]>

fixtures/Type/matches/HelloWorld.cos-ast

@@ -0,0 +1,9 @@
+class T { val x = 1; }
+----- -----
+T match {
+  case T => 1
+}
+-----
+T match {
+  case _ => 1
+}

fixtures/Type/matches/class.cos-ast

@@ -0,0 +1,5 @@
+class T { val x = 1; val y = 1; }
+----- -----
+T(x: 1, y: 2) match {
+  case T(x, y) => x + y
+}

fixtures/Type/matches/json.cos-ast

@@ -0,0 +1,18 @@
+class ValueT(T: Type) {
+  case Null;
+  case Elem(T);
+}
+val v1 = ValueT(i32).Null;
+val v2: ValueT(i32) = v1;
+----- -----
+ValueT(i32).Null match {
+  case ValueT(i32).Null => 1
+}
+-----
+v1 match {
+  case ValueT(i32).Null => 1
+}
+-----
+v2 match {
+  case ValueT(i32).Null => 1
+}

fixtures/Type/matches/nat.cos-ast

@@ -0,0 +1,25 @@
+class Nat {
+  case Zero
+  case Succ(Nat)
+};
+val v1 = Nat.Zero;
+val v2: Nat = Nat.Succ(Nat.Zero);
+----- -----
+Nat.Zero match {
+  case Nat.Zero => 1
+}
+-----
+Nat.Succ(Nat.Zero) match {
+  case Nat.Succ(Nat.Zero) => 1
+}
+-----
+v2 match {
+  case Nat.Zero => 0
+  case Nat.Succ(x) => 1
+}
+-----
+v2 match {
+  case Nat.Zero => 0
+  case Nat.Succ(Nat.Zero) => 1
+  case Nat.Succ(Nat.Succ(x)) => 2
+}

fixtures/Type/matches/number.cos-ast

@@ -0,0 +1,32 @@
+val n1 = 1
+----- -----
+1 match {
+  case 1 => 2
+}
+-----
+1 match {
+  case 0 => 2
+}
+-----
+n1 match {
+  case 1 => 3
+}
+-----
+n1 match {
+  case 0 => 4
+}
+-----
+1 match {
+  case 0 => 5
+  case 1 => 6
+}
+-----
+1 match {
+  case 0 => 7
+  case 1 => 8
+}
+-----
+n1 + 1 match {
+  case 0 => 3
+  case 1 => 4
+}

fixtures/Type/matches/result.cos-ast

@@ -0,0 +1,15 @@
+class Result[T, E] {
+  case Ok(T);
+  case Err(E);
+};
+val v0: Result(i32, i32) = Result(i32, i32).Ok(1);
+val v1 = v0;
+----- -----
+v0 match {
+  case Result(i32, i32).Ok(t) => t
+}
+-----
+v1 match {
+  case Result(i32, i32).Ok(t) => t
+  case Result(i32, i32).Err(e) => ???
+}

fixtures/Type/matches/string.cos-ast

@@ -0,0 +1,37 @@
+val v1 = "yes"
+----- -----
+"yes" match {
+  case "yes" => 1
+}
+-----
+"yes" match {
+  case "no" => 2
+}
+-----
+v1 match {
+  case "yes" => 3
+}
+-----
+v1 match {
+  case "no" => 4
+}
+-----
+"yes" match {
+  case "yes" => 5
+  case "no" => 6
+}
+-----
+"no" match {
+  case "yes" => 7
+  case "no" => 8
+}
+-----
+v1 match {
+  case "yes" => 5
+  case "no" => 6
+}
+-----
+v1 match {
+  case "yes" => 7
+  case "no" => 8
+}

fixtures/Type/patterns/HelloWorld.cos-ast

@@ -0,0 +1,3 @@
+class T { val x = 1; }
+-----
+T match T

fixtures/Type/patterns/class.cos-ast

@@ -0,0 +1,5 @@
+class T { val x = 1; }
+-----
+T(x: 1) match T
+T(x: 1) match T(x: 1)
+T match T(x: 1)

fixtures/Type/patterns/class2.cos-ast

@@ -0,0 +1,5 @@
+class T { val x = 1; val y = 1; }
+-----
+T(x: 1, y: 2) match T
+T(x: 1, y: 2) match T(x: 1)
+T(x: 1) match T(x: 1)

fixtures/Type/patterns/nat.cos-ast

@@ -0,0 +1,20 @@
+class Nat {
+  case Zero
+  case Succ(Nat)
+};
+val v1 = Nat.Zero;
+val v2 = Nat.Succ(Nat.Zero);
+-----
+Nat.Zero match Nat.Zero
+Nat.Zero match Nat.Succ(Nat.Zero)
+Nat.Succ(Nat.Zero) match Nat.Succ(Nat.Zero)
+Nat.Succ(Nat.Zero) match Nat.Succ
+Nat.Succ(Nat.Zero) match Nat
+v1 match Nat.Succ(Nat.Zero)
+v2 match Nat.Succ(Nat.Zero)
+v2 match Nat.Succ
+v2 match Nat
+Nat.Zero match Nat.Succ(t)
+v1 match Nat.Succ(t)
+Nat.Succ(Nat.Zero) match Nat.Succ(t)
+v2 match Nat.Succ(t)

fixtures/Type/patterns/result.cos-ast

@@ -0,0 +1,12 @@
+class Result[T, E] {
+  case Ok(T);
+  case Err(E);
+};
+val v0: Result(i32, i32) = Result(i32, i32).Ok(1);
+val v1 = v0;
+-----
+Result(i32, i32).Ok(1) match Result(i32, i32).Ok(1)
+Result(i32, i32).Ok(1) match Result(i32, i32).Ok(t)
+Result(i32, i32).Ok(1) match Result(i32, i32).Ok(1)
+v0 match Result(i32, i32).Ok(t)
+v1 match Result(i32, i32).Ok(t)

library/std/src/fmt.cos

@@ -1,4 +1,6 @@
 
+@noCore();
+
 import std::result;
 import std::str;
 

library/std/src/option.cos

@@ -1,4 +1,6 @@
 
+@noCore();
+
 class Option[T] {
   case Some(T);
   case None;

library/std/src/prelude/core.cos

@@ -1,4 +1,6 @@
 
+@noCore();
+
 import cSys from "@lib/c++/cstdlib"
 
 import _ from std::prelude::lang

library/std/src/prelude/core_stage1.cos

@@ -1,63 +1,12 @@
 
+@noCore();
+
 import "@lib/c++/cstdio"
-import "@lib/c++/string"
 import "@lib/c++/utility"
 import "@lib/c++/iostream"
 
 import _ from std::prelude::lang
 
-code("""
-// pub def str: Type = stringSys::std::string
-using str = std::string;
-template <typename T, typename Cond = void> struct DisplayTrait {};
-""")
-
-code("""
-
-template <typename T> inline void print(const T &x) {
-  using TT = std::decay_t<T>;
-  DisplayTrait<TT>::print(x);
-}
-
-template <typename T> inline void println(const T &x) {
-  using TT = std::decay_t<T>;
-  // todo: atomic print
-  DisplayTrait<TT>::print(x);
-  printf("\n");
-}
-
-template <> struct DisplayTrait<str> {
-  static void print(const str &x) { printf("%s", x.c_str()); }
-};
-
-template <> struct DisplayTrait<bool> {
-  static void print(bool x) {
-    if (x) {
-      printf("true");
-    } else {
-      printf("false");
-    }
-   }
-};
-template <typename T>
-struct DisplayTrait<
-    T, std::enable_if_t<std::is_integral_v<T> && std::is_signed_v<T>>> {
-  static void print(T x) { printf("%lld", static_cast<long long>(x)); }
-};
-
-template <typename T>
-struct DisplayTrait<
-    T, std::enable_if_t<std::is_integral_v<T> && std::is_unsigned_v<T>>> {
-  static void print(T x) { printf("%llu", static_cast<unsigned long long>(x)); }
-};
-template <> struct DisplayTrait<float32_t> {
-  static void print(float32_t x) { printf("%f", x); }
-};
-template <> struct DisplayTrait<float64_t> {
-  static void print(float64_t x) { printf("%lf", x); }
-};
-""")
-
 code("""
 
 [[noreturn]] inline void panic(const std::string& msg) {

library/std/src/prelude/lang.cos

@@ -1,16 +1,20 @@
 
+@noCore();
+
 import "@lib/c++/cstdint"
 import "@lib/c++/cinttypes"
 import "@lib/c++/cstdio"
 import "@lib/c++/memory"
 import "@lib/c++/variant"
 import "@lib/c++/tuple"
+import "@lib/c++/string"
 import cSys from "@lib/c++/cstdlib"
 
 code("""
 using float32_t = float;
 using float64_t = double;
 using float128_t = long double;
+using str = std::string;
 
 namespace cosmo {
 template<typename T, typename I, bool isMut = false, typename Cond = void>
@@ -28,3 +32,54 @@ struct Impl;
 }
 
 """);
+
+code("""
+// pub def str: Type = stringSys::std::string
+template <typename T, typename Cond = void> struct DisplayTrait {};
+""")
+
+code("""
+
+template <typename T> inline void print(const T &x) {
+  using TT = std::decay_t<T>;
+  DisplayTrait<TT>::print(x);
+}
+
+template <typename T> inline void println(const T &x) {
+  using TT = std::decay_t<T>;
+  // todo: atomic print
+  DisplayTrait<TT>::print(x);
+  printf("\n");
+}
+
+template <> struct DisplayTrait<str> {
+  static void print(const str &x) { printf("%s", x.c_str()); }
+};
+
+template <> struct DisplayTrait<bool> {
+  static void print(bool x) {
+    if (x) {
+      printf("true");
+    } else {
+      printf("false");
+    }
+   }
+};
+template <typename T>
+struct DisplayTrait<
+    T, std::enable_if_t<std::is_integral_v<T> && std::is_signed_v<T>>> {
+  static void print(T x) { printf("%lld", static_cast<long long>(x)); }
+};
+
+template <typename T>
+struct DisplayTrait<
+    T, std::enable_if_t<std::is_integral_v<T> && std::is_unsigned_v<T>>> {
+  static void print(T x) { printf("%llu", static_cast<unsigned long long>(x)); }
+};
+template <> struct DisplayTrait<float32_t> {
+  static void print(float32_t x) { printf("%f", x); }
+};
+template <> struct DisplayTrait<float64_t> {
+  static void print(float64_t x) { printf("%lf", x); }
+};
+""")