feat(furas): add slice type and instruction

furas/examples/array2.furas

@@ -1,6 +1,7 @@
 type arr = array $s8 10
+type arrSlice = slice $s8
 
-func println ref $arr = native println
+func println $arrSlice = native println
 
 public func main = #main
 main:
@@ -30,5 +31,8 @@ body:
 end:
     drop
     load %0
-    call ref $arr println
+    push $u32 0
+    load %1
+    slice
+    call $arrSlice println
     ret

furas/include/furas/token.hpp

@@ -34,6 +34,7 @@ struct token {
         // Instructions
         Push,
         Array,
+        Slice,
         Get,
         Set,
         Drop,

furas/src/gen.cpp

@@ -4,6 +4,7 @@
 #include "furvm/function.hpp"
 #include "furvm/fwd.hpp"
 #include "furvm/instruction.hpp"
+#include "furvm/module.hpp"
 
 #include <cassert>
 #include <cstdint>
@@ -24,6 +25,7 @@ namespace {
 // NOLINTBEGIN
 std::unordered_map<enum token::type, furvm::instruction_t> instructions = {
     { token::Array, furvm::instruction_t::Array },
+    { token::Slice, furvm::instruction_t::Slice },
     { token::Get, furvm::instruction_t::Get },
     { token::Set, furvm::instruction_t::Set },
     { token::Drop, furvm::instruction_t::Drop },
@@ -77,6 +79,7 @@ const char* token_type(enum token::type type) {
     case token::Allocate: return "allocate";
     case token::Push: return "push";
     case token::Array: return "array";
+    case token::Slice: return "slice";
     case token::Get: return "get";
     case token::Set: return "set";
     case token::Drop: return "drop";
@@ -160,6 +163,8 @@ struct mod_context {
         case furvm::mod_type::Array:
             return lhs->value.array.size == rhs->value.array.size &&
                    compare_types(mod.type_at(lhs->value.array.typeId), mod.type_at(rhs->value.array.typeId));
+        case furvm::mod_type::Slice:
+            return compare_types(mod.type_at(lhs->value.slice.typeId), mod.type_at(rhs->value.slice.typeId));
         case furvm::mod_type::Import:
             return lhs->value.imprt.modId == rhs->value.imprt.modId &&
                    lhs->value.imprt.typeId == rhs->value.imprt.typeId;
@@ -252,6 +257,15 @@ struct mod_context {
 
             return mod.emplace_type(inner.id(), size->value.uint);
         }
+        case token::Slice: {
+            auto result = next_token(lexer);
+
+            if (!result) throw std::runtime_error("error");
+
+            auto inner = eat_type(lexer, result.value);
+
+            return mod.emplace_type(furvm::mod_type::Slice, inner.id());
+        }
         default: throw std::runtime_error("error");
         }
     }
@@ -463,6 +477,7 @@ struct mod_context {
         }
 
         case token::Array:
+        case token::Slice:
         case token::Get:
         case token::Set:
         case token::Drop:

furas/src/lexer.cpp

@@ -43,6 +43,7 @@ token_r lexer::next_token() {
 
         { "push", token::Push },
         { "array", token::Array },
+        { "slice", token::Slice },
         { "get", token::Get },
         { "set", token::Set },
         { "drop", token::Drop },