From a88c502529b6649e25ffc832f0fdc25b6dba41f6 Mon Sep 17 00:00:00 2001
From: sfja <sfja2004@gmail.com>
Date: Fri, 13 Dec 2024 20:29:06 +0100
Subject: [PATCH] add readchar

---
 compiler/arch.ts |  7 ++++---
 examples/std.slg |  1 +
 runtime/arch.hpp |  7 ++++---
 runtime/vm.cpp   | 13 +++++++++++++
 4 files changed, 22 insertions(+), 6 deletions(-)

diff --git a/compiler/arch.ts b/compiler/arch.ts
index e8f9aee..4942416 100644
--- a/compiler/arch.ts
+++ b/compiler/arch.ts
@@ -55,9 +55,10 @@ export const Builtins = {
     FileOpen: 0x41,
     FileClose: 0x42,
     FileWriteString: 0x43,
-    FileReadToString: 0x44,
-    FileFlush: 0x45,
-    FileEof: 0x46,
+    FileReadChar: 0x44,
+    FileReadToString: 0x45,
+    FileFlush: 0x46,
+    FileEof: 0x47,
 } as const;
 
 export function opToString(op: number): string {
diff --git a/examples/std.slg b/examples/std.slg
index 24bf7e9..0175802 100644
--- a/examples/std.slg
+++ b/examples/std.slg
@@ -15,6 +15,7 @@ fn array_at_string(array: [string], index: int) -> string #[builtin(ArrayAt)] {}
 fn file_open(filename: string, mode: string) -> int #[builtin(FileOpen)] {}
 fn file_close(file: int) #[builtin(FileClose)] {}
 fn file_write_string(file: int, content: string) -> int #[builtin(FileWriteString)] {}
+fn file_read_char(file: int) -> int #[builtin(FileReadChar)] {}
 fn file_read_to_string(file: int) -> string #[builtin(FileReadToString)] {}
 fn file_flush(file: int) #[builtin(FileFlush)] {}
 fn file_eof(file: int) -> bool #[builtin(FileEof)] {}
diff --git a/runtime/arch.hpp b/runtime/arch.hpp
index 115f2f3..472b2fb 100644
--- a/runtime/arch.hpp
+++ b/runtime/arch.hpp
@@ -56,9 +56,10 @@ enum class Builtin : uint32_t {
     FileOpen = 0x41,
     FileClose = 0x42,
     FileWriteString = 0x43,
-    FileReadToString = 0x44,
-    FileFlush = 0x45,
-    FileEof = 0x46,
+    FileReadChar = 0x44,
+    FileReadToString = 0x45,
+    FileFlush = 0x46,
+    FileEof = 0x47,
 };
 
 }
diff --git a/runtime/vm.cpp b/runtime/vm.cpp
index 7e7fe48..97e2759 100644
--- a/runtime/vm.cpp
+++ b/runtime/vm.cpp
@@ -322,6 +322,7 @@ void VM::run_builtin(Builtin builtin_id)
         case Builtin::FileOpen:
         case Builtin::FileClose:
         case Builtin::FileWriteString:
+        case Builtin::FileReadChar:
         case Builtin::FileReadToString:
         case Builtin::FileFlush:
         case Builtin::FileEof:
@@ -488,6 +489,18 @@ void VM::run_file_builtin(Builtin builtin_id)
             stack_push(Int(0));
             break;
         }
+        case Builtin::FileReadChar: {
+            assert_stack_has(1);
+            auto file_id = stack_pop().as_int().value;
+            auto fp = this->open_files.find(file_id);
+            if (fp == this->open_files.end()) {
+                std::cerr << std::format("error: no open file {}\n", file_id);
+                std::exit(1);
+            }
+            int value = std::fgetc(fp->second);
+            stack_push(Int(value));
+            break;
+        }
         case Builtin::FileReadToString: {
             assert_stack_has(1);
             auto file_id = stack_pop().as_int().value;