From 7ddc8ba25d5929e8ef69b05fde43c1ef1602e62e Mon Sep 17 00:00:00 2001
From: lisyarus <lisyarus@gmail.com>
Date: Mon, 5 Jan 2026 00:36:11 +0300
Subject: [PATCH] Add f16 type & literals support in parser, type checker &
 interpreter

---
 libs/ast/include/pslang/ast/literal.hpp       |  3 ++
 libs/ast/source/print.cpp                     |  6 +++
 .../include/pslang/interpreter/value.hpp      |  2 +
 libs/interpreter/source/eval.cpp              | 13 +++++-
 libs/parser/rules/pslang.l                    |  2 +
 libs/parser/rules/pslang.y                    |  8 +++-
 .../types/include/pslang/types/half_float.hpp | 45 +++++++++++++++++++
 libs/types/include/pslang/types/primitive.hpp |  4 ++
 libs/types/source/print.cpp                   |  5 +++
 libs/types/source/type.cpp                    |  2 +-
 10 files changed, 87 insertions(+), 3 deletions(-)
 create mode 100644 libs/types/include/pslang/types/half_float.hpp

diff --git a/libs/ast/include/pslang/ast/literal.hpp b/libs/ast/include/pslang/ast/literal.hpp
index aeae7d5..33ec472 100644
--- a/libs/ast/include/pslang/ast/literal.hpp
+++ b/libs/ast/include/pslang/ast/literal.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include <pslang/types/half_float.hpp>
 #include <pslang/ast/location.hpp>
 
 #include <variant>
@@ -26,6 +27,7 @@ namespace pslang::ast
 	using i64_literal = primitive_literal_base<std::int64_t>;
 	using u64_literal = primitive_literal_base<std::uint64_t>;
 
+	using f16_literal = primitive_literal_base<types::half_float>;
 	using f32_literal = primitive_literal_base<float>;
 	using f64_literal = primitive_literal_base<double>;
 
@@ -39,6 +41,7 @@ namespace pslang::ast
 		u32_literal,
 		i64_literal,
 		u64_literal,
+		f16_literal,
 		f32_literal,
 		f64_literal
 	>;
diff --git a/libs/ast/source/print.cpp b/libs/ast/source/print.cpp
index 28408ca..c78a74f 100644
--- a/libs/ast/source/print.cpp
+++ b/libs/ast/source/print.cpp
@@ -148,6 +148,12 @@ namespace pslang::ast
 				out << "u64 literal { value = " << node.value << " }\n";
 			}
 
+			void apply(f16_literal const & node)
+			{
+				put_indent(out, options);
+				out << "f32 literal { value = " << std::setprecision(3) << node.value.repr << " }\n";
+			}
+
 			void apply(f32_literal const & node)
 			{
 				put_indent(out, options);
diff --git a/libs/interpreter/include/pslang/interpreter/value.hpp b/libs/interpreter/include/pslang/interpreter/value.hpp
index 2360b5d..c279288 100644
--- a/libs/interpreter/include/pslang/interpreter/value.hpp
+++ b/libs/interpreter/include/pslang/interpreter/value.hpp
@@ -34,6 +34,7 @@ namespace pslang::interpreter
 	using i64_value = primitive_value_base<std::int64_t>;
 	using u64_value = primitive_value_base<std::uint64_t>;
 
+	using f16_value = primitive_value_base<types::half_float>;
 	using f32_value = primitive_value_base<float>;
 	using f64_value = primitive_value_base<double>;
 
@@ -47,6 +48,7 @@ namespace pslang::interpreter
 		u32_value,
 		i64_value,
 		u64_value,
+		f16_value,
 		f32_value,
 		f64_value
 	>;
diff --git a/libs/interpreter/source/eval.cpp b/libs/interpreter/source/eval.cpp
index 7fce78e..ec4d7c4 100644
--- a/libs/interpreter/source/eval.cpp
+++ b/libs/interpreter/source/eval.cpp
@@ -336,7 +336,18 @@ namespace pslang::interpreter
 			}
 			else if constexpr (!std::is_same_v<T, bool> && !std::is_same_v<bool, H>)
 			{
-				return primitive_value(primitive_value_base<H>{static_cast<H>(value.value)});
+				if constexpr (std::is_same_v<T, types::half_float>)
+				{
+					return primitive_value(primitive_value_base<H>{static_cast<H>(value.value.repr)});
+				}
+				else if constexpr (std::is_same_v<H, types::half_float>)
+				{
+					return primitive_value(primitive_value_base<H>{{static_cast<float>(value.value)}});
+				}
+				else
+				{
+					return primitive_value(primitive_value_base<H>{static_cast<H>(value.value)});
+				}
 			}
 
 			std::ostringstream os;
diff --git a/libs/parser/rules/pslang.l b/libs/parser/rules/pslang.l
index e7705c7..b6b3cbc 100644
--- a/libs/parser/rules/pslang.l
+++ b/libs/parser/rules/pslang.l
@@ -46,6 +46,7 @@ i32  { return bp::make_i32(ctx.location); }
 u32  { return bp::make_u32(ctx.location); }
 i64  { return bp::make_i64(ctx.location); }
 u64  { return bp::make_u64(ctx.location); }
+f16  { return bp::make_f16(ctx.location); }
 f32  { return bp::make_f32(ctx.location); }
 f64  { return bp::make_f64(ctx.location); }
 
@@ -88,6 +89,7 @@ f64  { return bp::make_f64(ctx.location); }
 [0-9]+ul { return bp::make_lit_u64(yytext, ctx.location); }
 
 [0-9]+\.[0-9]+  { return bp::make_lit_f32(yytext, ctx.location); }
+[0-9]+\.[0-9]+h { return bp::make_lit_f16(yytext, ctx.location); }
 [0-9]+\.[0-9]+l { return bp::make_lit_f64(yytext, ctx.location); }
 
 '.' { return bp::make_lit_char8(yytext[1], ctx.location); }
diff --git a/libs/parser/rules/pslang.y b/libs/parser/rules/pslang.y
index 77ea339..17541d2 100644
--- a/libs/parser/rules/pslang.y
+++ b/libs/parser/rules/pslang.y
@@ -48,7 +48,9 @@ template <typename T>
 {
 	T value;
 #ifdef __clang__
-	if constexpr (std::is_floating_point_v<T>)
+	if constexpr (std::is_same_v<T, ::pslang::types::half_float>)
+		value = {float(std::atof(str.data()))};
+	else if constexpr (std::is_floating_point_v<T>)
 		value = std::atof(str.data());
 	else if constexpr (std::is_signed_v<T>)
 		value = std::strtoll(str.data(), nullptr, 10);
@@ -137,6 +139,7 @@ template <typename T>
 %token u32
 %token i64
 %token u64
+%token f16
 %token f32
 %token f64
 
@@ -259,6 +262,7 @@ primitive_type
 | u32  { $$ = types::u32_type{}; }
 | i64  { $$ = types::i64_type{}; }
 | u64  { $$ = types::u64_type{}; }
+| f16  { $$ = types::f16_type{}; }
 | f32  { $$ = types::f32_type{}; }
 | f64  { $$ = types::f64_type{}; }
 ;
@@ -309,6 +313,7 @@ postfix_expression
 | u32 lparen comma_separated_expression_list rparen { $$ = ast::function_call{nullptr, std::make_unique<ast::type>(types::u32_type{}), $3, @$}; }
 | i64 lparen comma_separated_expression_list rparen { $$ = ast::function_call{nullptr, std::make_unique<ast::type>(types::i64_type{}), $3, @$}; }
 | u64 lparen comma_separated_expression_list rparen { $$ = ast::function_call{nullptr, std::make_unique<ast::type>(types::u64_type{}), $3, @$}; }
+| f16 lparen comma_separated_expression_list rparen { $$ = ast::function_call{nullptr, std::make_unique<ast::type>(types::f16_type{}), $3, @$}; }
 | f32 lparen comma_separated_expression_list rparen { $$ = ast::function_call{nullptr, std::make_unique<ast::type>(types::f32_type{}), $3, @$}; }
 | f64 lparen comma_separated_expression_list rparen { $$ = ast::function_call{nullptr, std::make_unique<ast::type>(types::f64_type{}), $3, @$}; }
 ;
@@ -341,6 +346,7 @@ literal
 | lit_u32 { $$ = parse_primitive_literal<std::uint32_t>($1, ctx.location); }
 | lit_i64 { $$ = parse_primitive_literal<std::int64_t>($1, ctx.location); }
 | lit_u64 { $$ = parse_primitive_literal<std::uint64_t>($1, ctx.location); }
+| lit_f16 { $$ = parse_primitive_literal<types::half_float>($1, ctx.location); }
 | lit_f32 { $$ = parse_primitive_literal<float>($1, ctx.location); }
 | lit_f64 { $$ = parse_primitive_literal<double>($1, ctx.location); }
 | lit_char8 { $$ = ast::u8_literal{static_cast<std::uint8_t>($1), ctx.location}; }
diff --git a/libs/types/include/pslang/types/half_float.hpp b/libs/types/include/pslang/types/half_float.hpp
new file mode 100644
index 0000000..8b22d30
--- /dev/null
+++ b/libs/types/include/pslang/types/half_float.hpp
@@ -0,0 +1,45 @@
+#pragma once
+
+#include <pslang/types/half_float.hpp>
+
+#include <compare>
+
+namespace pslang::types
+{
+
+	// TODO: actual half-float operations? Maybe C++23 std::float16_t?
+
+	struct half_float
+	{
+		float repr = 0.f;
+
+		friend bool operator == (half_float const &, half_float const &) = default;
+		friend auto operator <=> (half_float const &, half_float const &) = default;
+	};
+
+	inline half_float operator - (half_float f)
+	{
+		return {-f.repr};
+	}
+
+	inline half_float operator + (half_float f1, half_float f2)
+	{
+		return {f1.repr + f2.repr};
+	}
+
+	inline half_float operator - (half_float f1, half_float f2)
+	{
+		return {f1.repr - f2.repr};
+	}
+
+	inline half_float operator * (half_float f1, half_float f2)
+	{
+		return {f1.repr * f2.repr};
+	}
+
+	inline half_float operator / (half_float f1, half_float f2)
+	{
+		return {f1.repr / f2.repr};
+	}
+
+}
\ No newline at end of file
diff --git a/libs/types/include/pslang/types/primitive.hpp b/libs/types/include/pslang/types/primitive.hpp
index 3ea7fde..b24876a 100644
--- a/libs/types/include/pslang/types/primitive.hpp
+++ b/libs/types/include/pslang/types/primitive.hpp
@@ -1,5 +1,7 @@
 #pragma once
 
+#include <pslang/types/half_float.hpp>
+
 #include <variant>
 #include <cstdint>
 
@@ -29,6 +31,7 @@ namespace pslang::types
 	using i64_type = primitive_type_base<std::int64_t>;
 	using u64_type = primitive_type_base<std::uint64_t>;
 
+	using f16_type = primitive_type_base<half_float>;
 	using f32_type = primitive_type_base<float>;
 	using f64_type = primitive_type_base<double>;
 
@@ -42,6 +45,7 @@ namespace pslang::types
 		u32_type,
 		i64_type,
 		u64_type,
+		f16_type,
 		f32_type,
 		f64_type
 	>;
diff --git a/libs/types/source/print.cpp b/libs/types/source/print.cpp
index a54bf26..cf1a62c 100644
--- a/libs/types/source/print.cpp
+++ b/libs/types/source/print.cpp
@@ -64,6 +64,11 @@ namespace pslang::types
 				out << "u64";
 			}
 
+			void apply(f16_type const &)
+			{
+				out << "f16";
+			}
+
 			void apply(f32_type const &)
 			{
 				out << "f32";
diff --git a/libs/types/source/type.cpp b/libs/types/source/type.cpp
index e78897d..1d32638 100644
--- a/libs/types/source/type.cpp
+++ b/libs/types/source/type.cpp
@@ -93,7 +93,7 @@ namespace pslang::types
 		{
 			return std::visit([]<typename T>(primitive_type_base<T> const &)
 			{
-				return std::is_floating_point_v<T>;
+				return std::is_floating_point_v<T> || std::is_same_v<T, types::half_float>;
 			}, *ptype);
 		}