Implement IO.read

builtin/io.wren

@@ -78,4 +78,9 @@ class IO {
     IO.writeString_(obj.toString)
     return obj
   }
+
+  static read(prompt) {
+    IO.write(prompt)
+    return IO.read
+  }
 }

src/wren_io.c

@@ -3,8 +3,12 @@
 #if WREN_USE_LIB_IO
 
 #include <stdio.h>
+#include <string.h>
 #include <time.h>
 
+// TODO: this is a somewhat arbitrary limit, do something smarter?
+#define MAX_READ_LEN 1024
+
 // This string literal is generated automatically from io.wren. Do not edit.
 static const char* libSource =
 "class IO {\n"
@@ -87,6 +91,11 @@ static const char* libSource =
 "    IO.writeString_(obj.toString)\n"
 "    return obj\n"
 "  }\n"
+"\n"
+"  static read(prompt) {\n"
+"    IO.write(prompt)\n"
+"    return IO.read\n"
+"  }\n"
 "}\n";
 
 static void ioWriteString(WrenVM* vm)
@@ -96,6 +105,18 @@ static void ioWriteString(WrenVM* vm)
   printf("%s", s);
 }
 
+static void ioRead(WrenVM* vm)
+{
+  char buffer[MAX_READ_LEN];
+  char* result = fgets(buffer, MAX_READ_LEN, stdin);
+
+  if (result == NULL) {
+    // TODO: handle error here
+  }
+
+  wrenReturnString(vm, buffer, strlen(buffer));
+}
+
 static void ioClock(WrenVM* vm)
 {
   wrenReturnDouble(vm, (double)clock() / CLOCKS_PER_SEC);
@@ -106,6 +127,7 @@ void wrenLoadIOLibrary(WrenVM* vm)
   wrenInterpret(vm, "Wren IO library", libSource);
   wrenDefineStaticMethod(vm, "IO", "writeString_", 1, ioWriteString);
   wrenDefineStaticMethod(vm, "IO", "clock", 0, ioClock);
+  wrenDefineStaticMethod(vm, "IO", "read", 0, ioRead);
 }
 
 #endif