term library added

src/core/compiler.c

@@ -485,12 +485,6 @@ struct Compiler {
   // such assignments.
   bool can_define;
 
-  // This value will set to true for parsing a temproary expression
-  // (ie. if <expr> ...) and the value of the expression will be popped out of
-  // the stack onece we're done, if it's a defenition, that value should be
-  // duplicated on the stack to prevent it.
-  bool expr_temp;
-
   // This value will be true after parsing a call expression, for every other
   // Expressions it'll be false. This is **ONLY** to be used when compiling a
   // return statement to check if the last parsed expression is a call to
@@ -1896,13 +1890,10 @@ static void exprInterpolation(Compiler* compiler) {
 
 static void exprFunction(Compiler* compiler) {
   bool can_define = compiler->can_define;
-  bool expr_temp = compiler->expr_temp;
 
   compiler->can_define = true;
-  compiler->expr_temp = false;
   compileFunction(compiler, FUNC_LITERAL);
   compiler->can_define = can_define;
-  compiler->expr_temp = expr_temp;
 }
 
 static void exprName(Compiler* compiler) {
@@ -1994,10 +1985,6 @@ static void exprName(Compiler* compiler) {
       ASSERT(compiler->parser.has_errors ||
              (compiler->func->stack_size - 1) == index, OOPS);
 
-      if (compiler->expr_temp) {
-        emitOpcode(compiler, OP_DUP);
-      }
-
     } else {
       // The assigned value or the result of the operator will be at the top of
       // the stack by now. Store it.
@@ -3087,10 +3074,10 @@ static void compileIfStatement(Compiler* compiler, bool elif) {
 
   skipNewLines(compiler);
 
-  bool expr_temp = compiler->expr_temp;
+  bool can_define = compiler->can_define;
-  compiler->expr_temp = true;
+  compiler->can_define = false;
   compileExpression(compiler); //< Condition.
-  compiler->expr_temp = expr_temp;
+  compiler->can_define = can_define;
 
   emitOpcode(compiler, OP_JUMP_IF_NOT);
   int ifpatch = emitShort(compiler, 0xffff); //< Will be patched.
@@ -3140,10 +3127,10 @@ static void compileWhileStatement(Compiler* compiler) {
   loop.depth = compiler->scope_depth;
   compiler->loop = &loop;
 
-  bool expr_temp = compiler->expr_temp;
+  bool can_define = compiler->can_define;
-  compiler->expr_temp = true;
+  compiler->can_define = false;
   compileExpression(compiler); //< Condition.
-  compiler->expr_temp = expr_temp;
+  compiler->can_define = can_define;
 
   emitOpcode(compiler, OP_JUMP_IF_NOT);
   int whilepatch = emitShort(compiler, 0xffff); //< Will be patched.
@@ -3176,10 +3163,10 @@ static void compileForStatement(Compiler* compiler) {
 
   // Compile and store sequence.
   compilerAddVariable(compiler, "@Sequence", 9, iter_line); // Sequence
-  bool expr_temp = compiler->expr_temp;
+  bool can_define = compiler->can_define;
-  compiler->expr_temp = true;
+  compiler->can_define = false;
   compileExpression(compiler);
-  compiler->expr_temp = expr_temp;
+  compiler->can_define = can_define;
 
   // Add iterator to locals. It's an increasing integer indicating that the
   // current loop is nth starting from 0.

src/libs/ext_term.c

@@ -0,0 +1,259 @@
+/*
+ *  Copyright (c) 2020-2022 Thakee Nathees
+ *  Copyright (c) 2021-2022 Pocketlang Contributors
+ *  Distributed Under The MIT License
+ */
+
+#ifndef PK_AMALGAMATED
+#include "libs.h"
+#endif
+
+#define TERM_IMPLEMENT
+#include "thirdparty/term/term.h"  //<< AMALG_INLINE >>
+#undef TERM_IMPLEMENT
+
+// A reference to the event class, to check is instance of.
+static PkHandle* _cls_term_event = NULL;
+
+static void _setSlotVector(PKVM* vm, int slot, int tmp, double x, double y) {
+
+  if (!pkImportModule(vm, "types", slot)) return;
+  if (!pkGetAttribute(vm, slot, "Vector", slot)) return;
+  if (!pkNewInstance(vm, slot, slot, 0, 0)) return;
+
+  pkSetSlotNumber(vm, tmp, x);
+  if (!pkSetAttribute(vm, slot, "x", tmp)) return;
+  pkSetSlotNumber(vm, tmp, y);
+  if (!pkSetAttribute(vm, slot, "y", tmp)) return;
+}
+
+void* _termEventNew(PKVM* vm) {
+  term_Event* event = pkRealloc(vm, NULL, sizeof(term_Event));
+  event->type = TERM_ET_UNKNOWN;
+  return event;
+}
+
+void _termEventDelete(PKVM* vm, void* event) {
+  pkRealloc(vm, event, 0);
+}
+
+void _termEventGetter(PKVM* vm) {
+  const char* name;
+  if (!pkValidateSlotString(vm, 1, &name, NULL)) return;
+
+  term_Event* event = pkGetSelf(vm);
+
+  if (strcmp(name, "type") == 0) {
+    pkSetSlotNumber(vm, 0, (double)event->type);
+
+  } else if (strcmp(name, "keycode") == 0) {
+    pkSetSlotNumber(vm, 0, (double)event->key.code);
+
+  } else if (strcmp(name, "ascii") == 0) {
+    pkSetSlotNumber(vm, 0, (double)event->key.ascii);
+
+  } else if (strcmp(name, "modifiers") == 0) {
+    if (event->type == TERM_ET_KEY_DOWN) {
+      pkSetSlotNumber(vm, 0, (double)event->key.modifiers);
+    } else {
+      pkSetSlotNumber(vm, 0, (double)event->mouse.modifiers);
+    }
+
+  } else if (strcmp(name, "button") == 0) {
+    pkSetSlotNumber(vm, 0, (double)event->mouse.button);
+
+  } else if (strcmp(name, "pos") == 0) {
+    pkReserveSlots(vm, 2);
+    _setSlotVector(vm, 0, 1, event->mouse.pos.x, event->mouse.pos.y);
+
+  } else if (strcmp(name, "scroll") == 0) {
+    pkSetSlotBool(vm, 0, event->mouse.scroll);
+  }
+
+}
+
+void _registerEnums(PKVM* vm, PkHandle* term) {
+  pkReserveSlots(vm, 1);
+  pkSetSlotHandle(vm, 0, term);
+
+  pkSetSlotNumber(vm, 1, TERM_KEY_UNKNOWN); pkSetAttribute(vm, 0, "KEY_UNKNOWN", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_0); pkSetAttribute(vm, 0, "KEY_0", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_1); pkSetAttribute(vm, 0, "KEY_1", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_2); pkSetAttribute(vm, 0, "KEY_2", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_3); pkSetAttribute(vm, 0, "KEY_3", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_4); pkSetAttribute(vm, 0, "KEY_4", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_5); pkSetAttribute(vm, 0, "KEY_5", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_6); pkSetAttribute(vm, 0, "KEY_6", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_7); pkSetAttribute(vm, 0, "KEY_7", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_8); pkSetAttribute(vm, 0, "KEY_8", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_9); pkSetAttribute(vm, 0, "KEY_9", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_A); pkSetAttribute(vm, 0, "KEY_A", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_B); pkSetAttribute(vm, 0, "KEY_B", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_C); pkSetAttribute(vm, 0, "KEY_C", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_D); pkSetAttribute(vm, 0, "KEY_D", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_E); pkSetAttribute(vm, 0, "KEY_E", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F); pkSetAttribute(vm, 0, "KEY_F", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_G); pkSetAttribute(vm, 0, "KEY_G", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_H); pkSetAttribute(vm, 0, "KEY_H", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_I); pkSetAttribute(vm, 0, "KEY_I", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_J); pkSetAttribute(vm, 0, "KEY_J", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_K); pkSetAttribute(vm, 0, "KEY_K", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_L); pkSetAttribute(vm, 0, "KEY_L", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_M); pkSetAttribute(vm, 0, "KEY_M", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_N); pkSetAttribute(vm, 0, "KEY_N", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_O); pkSetAttribute(vm, 0, "KEY_O", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_P); pkSetAttribute(vm, 0, "KEY_P", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_Q); pkSetAttribute(vm, 0, "KEY_Q", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_R); pkSetAttribute(vm, 0, "KEY_R", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_S); pkSetAttribute(vm, 0, "KEY_S", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_T); pkSetAttribute(vm, 0, "KEY_T", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_U); pkSetAttribute(vm, 0, "KEY_U", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_V); pkSetAttribute(vm, 0, "KEY_V", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_W); pkSetAttribute(vm, 0, "KEY_W", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_X); pkSetAttribute(vm, 0, "KEY_X", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_Y); pkSetAttribute(vm, 0, "KEY_Y", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_Z); pkSetAttribute(vm, 0, "KEY_Z", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_ESC); pkSetAttribute(vm, 0, "KEY_ESC", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_ENTER); pkSetAttribute(vm, 0, "KEY_ENTER", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_SPACE); pkSetAttribute(vm, 0, "KEY_SPACE", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_HOME); pkSetAttribute(vm, 0, "KEY_HOME", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_END); pkSetAttribute(vm, 0, "KEY_END", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_PAGEUP); pkSetAttribute(vm, 0, "KEY_PAGEUP", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_PAGEDOWN); pkSetAttribute(vm, 0, "KEY_PAGEDOWN", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_LEFT); pkSetAttribute(vm, 0, "KEY_LEFT", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_UP); pkSetAttribute(vm, 0, "KEY_UP", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_RIGHT); pkSetAttribute(vm, 0, "KEY_RIGHT", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_DOWN); pkSetAttribute(vm, 0, "KEY_DOWN", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_INSERT); pkSetAttribute(vm, 0, "KEY_INSERT", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_DELETE); pkSetAttribute(vm, 0, "KEY_DELETE", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_BACKSPACE); pkSetAttribute(vm, 0, "KEY_BACKSPACE", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_TAB); pkSetAttribute(vm, 0, "KEY_TAB", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F1); pkSetAttribute(vm, 0, "KEY_F1", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F2); pkSetAttribute(vm, 0, "KEY_F2", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F3); pkSetAttribute(vm, 0, "KEY_F3", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F4); pkSetAttribute(vm, 0, "KEY_F4", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F5); pkSetAttribute(vm, 0, "KEY_F5", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F6); pkSetAttribute(vm, 0, "KEY_F6", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F7); pkSetAttribute(vm, 0, "KEY_F7", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F8); pkSetAttribute(vm, 0, "KEY_F8", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F9); pkSetAttribute(vm, 0, "KEY_F9", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F10); pkSetAttribute(vm, 0, "KEY_F10", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F11); pkSetAttribute(vm, 0, "KEY_F11", 1);
+  pkSetSlotNumber(vm, 1, TERM_KEY_F12); pkSetAttribute(vm, 0, "KEY_F12", 1);
+
+  pkSetSlotNumber(vm, 1, TERM_MB_UNKNOWN); pkSetAttribute(vm, 0, "BUTTON_UNKNOWN", 1);
+  pkSetSlotNumber(vm, 1, TERM_MB_LEFT); pkSetAttribute(vm, 0, "BUTTON_LEFT", 1);
+  pkSetSlotNumber(vm, 1, TERM_MB_MIDDLE); pkSetAttribute(vm, 0, "BUTTON_MIDDLE", 1);
+  pkSetSlotNumber(vm, 1, TERM_MB_RIGHT); pkSetAttribute(vm, 0, "BUTTON_RIGHT", 1);
+
+  pkSetSlotNumber(vm, 1, TERM_MD_NONE); pkSetAttribute(vm, 0, "MD_NONE", 1);
+  pkSetSlotNumber(vm, 1, TERM_MD_CTRL); pkSetAttribute(vm, 0, "MD_CTRL", 1);
+  pkSetSlotNumber(vm, 1, TERM_MD_ALT); pkSetAttribute(vm, 0, "MD_ALT", 1);
+  pkSetSlotNumber(vm, 1, TERM_MD_SHIFT); pkSetAttribute(vm, 0, "MD_SHIFT", 1);
+
+  pkSetSlotNumber(vm, 1, TERM_ET_UNKNOWN); pkSetAttribute(vm, 0, "EVENT_UNKNOWN", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_KEY_DOWN); pkSetAttribute(vm, 0, "EVENT_KEY_DOWN", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_RESIZE); pkSetAttribute(vm, 0, "EVENT_RESIZE", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_DOUBLE_CLICK); pkSetAttribute(vm, 0, "EVENT_DOUBLE_CLICK", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_MOUSE_DOWN); pkSetAttribute(vm, 0, "EVENT_MOUSE_DOWN", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_MOUSE_UP); pkSetAttribute(vm, 0, "EVENT_MOUSE_UP", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_MOUSE_MOVE); pkSetAttribute(vm, 0, "EVENT_MOUSE_MOVE", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_MOUSE_DRAG); pkSetAttribute(vm, 0, "EVENT_MOUSE_DRAG", 1);
+  pkSetSlotNumber(vm, 1, TERM_ET_MOUSE_SCROLL); pkSetAttribute(vm, 0, "EVENT_MOUSE_SCROLL", 1);
+
+}
+
+void _termInit(PKVM* vm) {
+  bool capture_events;
+  if (!pkValidateSlotBool(vm, 1, &capture_events)) return;
+  term_init(capture_events);
+}
+
+void _termCleanup(PKVM* vm) {
+  term_cleanup();
+}
+
+void _termIsatty(PKVM* vm) {
+  pkSetSlotBool(vm, 0, term_isatty());
+}
+
+void _termNewScreenBuffer(PKVM* vm) {
+  term_new_screen_buffer();
+}
+
+void _termRestoreScreenBuffer(PKVM* vm) {
+  term_restore_screen_buffer();
+}
+
+void _termGetSize(PKVM* vm) {
+  pkReserveSlots(vm, 2);
+  term_Vec size = term_getsize();
+  _setSlotVector(vm, 0, 1, size.x, size.y);
+}
+
+void _termGetPosition(PKVM* vm) {
+  pkReserveSlots(vm, 2);
+  term_Vec pos = term_getposition();
+  _setSlotVector(vm, 0, 1, pos.x, pos.y);
+}
+
+void _termSetPosition(PKVM* vm) {
+  double x, y;
+
+  int argc = pkGetArgc(vm);
+  if (!pkCheckArgcRange(vm, argc, 1, 2)) return;
+
+  if (argc == 1) {
+    pkReserveSlots(vm, 3);
+    if (!pkGetAttribute(vm, 1, "x", 2)) return;
+    if (!pkValidateSlotNumber(vm, 2, &x)) return;
+
+    if (!pkGetAttribute(vm, 1, "y", 2)) return;
+    if (!pkValidateSlotNumber(vm, 2, &y)) return;
+  } else {
+    if (!pkValidateSlotNumber(vm, 1, &x)) return;
+    if (!pkValidateSlotNumber(vm, 2, &y)) return;
+  }
+
+  term_Vec pos = term_vec((int)x, (int)y);
+  term_setposition(pos);
+}
+
+void _termReadEvent(PKVM* vm) {
+  pkReserveSlots(vm, 3);
+  pkSetSlotHandle(vm, 2, _cls_term_event);
+  if (!pkValidateSlotInstanceOf(vm, 1, 2)) return;
+
+  term_Event* event = pkGetSlotNativeInstance(vm, 1);
+  pkSetSlotBool(vm, 0, term_read_event(event));
+}
+
+/*****************************************************************************/
+/* MODULE REGISTER                                                           */
+/*****************************************************************************/
+
+void registerModuleTerm(PKVM* vm) {
+  PkHandle* term = pkNewModule(vm, "term");
+
+  _registerEnums(vm, term);
+  pkModuleAddFunction(vm, term, "init", _termInit, 1);
+  pkModuleAddFunction(vm, term, "cleanup", _termCleanup, 0);
+  pkModuleAddFunction(vm, term, "isatty", _termIsatty, 0);
+  pkModuleAddFunction(vm, term, "new_screen_buffer", _termNewScreenBuffer, 0);
+  pkModuleAddFunction(vm, term, "restore_screen_buffer", _termRestoreScreenBuffer, 0);
+  pkModuleAddFunction(vm, term, "getsize", _termGetSize, 0);
+  pkModuleAddFunction(vm, term, "getposition", _termGetPosition, 0);
+  pkModuleAddFunction(vm, term, "setposition", _termSetPosition, -1);
+  pkModuleAddFunction(vm, term, "read_event", _termReadEvent, 1);
+
+  _cls_term_event = pkNewClass(vm, "Event", NULL, term, _termEventNew, _termEventDelete);
+  pkClassAddMethod(vm, _cls_term_event, "@getter", _termEventGetter, 1);
+
+  pkRegisterModule(vm, term);
+  pkReleaseHandle(vm, term);
+}
+
+void cleanupModuleTerm(PKVM* vm) {
+  if (_cls_term_event) pkReleaseHandle(vm, _cls_term_event);
+}
+

src/libs/libs.c

@@ -17,6 +17,9 @@ void registerModuleIO(PKVM* vm);
 void registerModulePath(PKVM* vm);
 void registerModuleDummy(PKVM* vm);
 
+void registerModuleTerm(PKVM* vm);
+void cleanupModuleTerm(PKVM* vm);
+
 // Registers the modules.
 void registerLibs(PKVM* vm) {
   registerModuleMath(vm);
@@ -25,8 +28,11 @@ void registerLibs(PKVM* vm) {
   registerModuleIO(vm);
   registerModulePath(vm);
   registerModuleDummy(vm);
+
+  registerModuleTerm(vm);
 }
 
 // Cleanup the modules.
 void cleanupLibs(PKVM* vm) {
+  cleanupModuleTerm(vm);
 }

src/libs/thirdparty/term/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2022 Thakee Nathees
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.

tests/examples/snake.pk

@@ -0,0 +1,124 @@
+
+import tui, term, math
+from types import Vector
+
+## This is a pocketlang implementation of:
+## https://www.youtube.com/watch?v=xGmXxpIj6vs&t=279s&ab_channel=ChrisDeLeonofHomeTeamGameDev
+
+## x, y velocity of snake.
+vx = 0; vy = 0
+
+## position (at the middle).
+px = 0; py = 0
+
+## tile size.
+tx = 0; ty = 0
+
+## apple position.
+ax = 15; ay = 15
+
+## tail, trail
+trail = []
+tail = 15
+
+## score
+score = 0
+
+def init()
+  size = tui.get_size()
+  tx = size.x
+  ty = size.y
+  
+  px = tx / 2; py = ty / 2
+end
+
+def frame()
+  px += vx
+  py += vy
+  if px < 0 then px = tx - 1 end
+  if px > tx - 1 then px = 0 end
+  if py < 0 then py = ty - 1 end
+  if py > ty - 1 then py = 0 end
+  
+  tui.clear()
+  tui.string('press Q to quit | score = $score')
+  
+  for i in trail
+    tui.set_position(i.x, i.y)
+    tui.start_bg(0, 0xff, 0)
+    tui.string(' ')
+    tui.end_bg()
+    
+    if i.x == px and i.y == py
+      tail = 5
+    end
+  end
+  
+  tui.set_position(ax, ay)
+  tui.start_bg(0xff, 0, 0)
+  tui.string(' ')
+  tui.end_bg()
+  
+  trail.append(Vector(px, py))
+  while trail.length > tail
+    trail.pop(0)
+  end
+  
+  if px == ax and py == ay
+    tail += 1
+    score += 1
+    ax = math.rand() % tx
+    ay = math.rand() % ty
+  end
+  tui.flush()
+end
+
+def handle(event)
+  if event.type == term.EVENT_KEY_DOWN
+    if event.keycode == term.KEY_Q
+      tui.stop()
+    end
+    
+    ## The "Switch Statement" alternative.
+    {
+      term.KEY_LEFT: fn
+        vx = -1; vy = 0
+      end,
+      
+      term.KEY_UP: fn
+        vx = 0; vy = -1
+      end,
+      
+      term.KEY_DOWN: fn
+        vx = 0; vy = 1
+      end,
+      
+      term.KEY_RIGHT: fn
+        vx = 1; vy = 0
+      end,
+      
+      term.KEY_T: fn
+        math.sin(12)
+      end,
+
+    }.get(event.keycode, fn end)()
+  
+  end
+end
+
+
+def main()
+  config = tui.Config()
+  config.capture_events = true
+  config.hide_cursor = true
+  config.new_buffer = true
+  config.fps = 20
+  config.init_fn = init
+  config.event_fn = handle
+  config.frame_fn = frame
+  tui.run(config)
+end
+
+
+main()
+

tests/examples/tui/_init.pk

@@ -0,0 +1,321 @@
+
+import term, io
+from time import clock, sleep
+from types import ByteBuffer
+
+def write(msg)
+  io.write(io.stdout, msg)
+end
+
+## The configuration that should be used to create tui context
+## and run.
+class Config
+  def _init()
+    self.title = null
+    self.fps = 60
+    self.hide_cursor = false
+    self.capture_events = false
+    self.new_buffer = false
+
+    self.init_fn = null
+    self.event_fn = null
+    self.frame_fn = null
+    self.cleanup_fn = null    
+  end
+end
+
+## Interlan context contains draw buffer and other data.
+class _Context
+  def _init()
+    self.buff = ByteBuffer()
+    self.clear()
+  end
+  
+  ## Called to reset all the internal for reusing the context.
+  def clear()
+    self.buff.clear()
+    self.done = false ## If true the main loop ends.
+  end
+end
+
+## Internal global context.
+_ctx = _Context()
+
+## -------------------------------------------------------------------------
+## FUNCTIONS
+## -------------------------------------------------------------------------
+
+## Flush all the buffered bytes in the context's buffer.
+def flush()
+  write(_ctx.buff.string())
+  io.flush()
+  _ctx.buff.clear()
+end
+
+## Stops the main loop and return from run().
+def stop()
+  _ctx.done = true
+end
+
+def set_title(title)
+  write("\x1b]0;$title\x07")
+end
+
+def hide_cursor()
+  write("\x1b[?25l")
+end
+
+def show_cursor()
+  write("\x1b[?25h")
+end
+
+## It'll write escape sequence to move the cursor but not actually move.
+## for this to make effect, one should flush the buffer.
+def set_position(x, y)
+  _ctx.buff.write("\x1b[${y + 1};${x + 1}H")
+end
+
+def get_size()
+  return term.getsize()
+end
+
+## 
+## Hex    ASCII  DEC-Line-Drawing
+## ------------------------------
+##  0x6a    j        ┘
+##  0x6b    k        ┐
+##  0x6c    l        ┌
+##  0x6d    m        └
+##  0x6e    n        ┼
+##  0x71    q        ─
+##  0x74    t        ├
+##  0x75    u        ┤
+##  0x76    v        ┴
+##  0x77    w        ┬
+##  0x78    x        │
+##
+def box_char(c)
+  _ctx.buff.write("\x1b(0$c\x1b(B")
+end
+
+## FIXME: Implement str * int multiplicatin to support
+##
+##     "\x1b(0${ c * n }\x1b(B"
+##
+## and define box_char_len() or refactor the above to take argument n.
+
+## Write a string to the context buffer.
+def string(s)
+  _ctx.buff.write(str(s))
+end
+
+## Clear the screen and move cursor to (0, 0).
+def clear()
+  _ctx.buff.write("\x1b[H\x1b[J")
+end
+
+## Clear everythin from cursor to EOL.
+def clear_eol()
+  _ctx.buff.write("\x1b[K")
+end
+
+## Clear everythin from cursor to EOF.
+def clear_eof()
+  _ctx.buff.write("\x1b[J")
+end
+
+## Reset all the stylings.
+def reset()
+  _ctx.buff.write("\x1b[0m")
+end
+
+def _is_valid_color(r, g, b)
+  return r is Number and g is Number and b is Number
+  return r.isbyte() and g.isbyte() and b.isbyte()
+end
+
+## Set the forground color.
+def start_color(r, g, b)
+  assert(_is_valid_color(r, g, b))
+  _ctx.buff.write("\x1b[38;2;$r;$g;${b}m")
+end
+
+## End the forground color.
+def end_color()
+  _ctx.buff.write("\x1b[39m")
+end
+
+## Start the background color.
+def start_bg(r, g, b)
+  assert(_is_valid_color(r, g, b))
+  _ctx.buff.write("\x1b[48;2;$r;$g;${b}m")
+end
+
+## End the background color.
+def end_bg()
+  _ctx.buff.write("\x1b[49m")
+end
+
+def start_bold()
+  _ctx.buff.write("\x1b[1m")
+end
+
+def end_bold()
+  _ctx.buff.write("\x1b[22m")
+end
+
+def start_dim()
+  _ctx.buff.write("\x1b[2m")
+end
+
+def end_dim()
+  _ctx.buff.write("\x1b[22m")
+end
+
+def start_italic()
+  _ctx.buff.write("\x1b[3m")
+end
+
+def end_italic()
+  _ctx.buff.write("\x1b[23m")
+end
+
+def start_underline()
+  _ctx.buff.write("\x1b[4m")
+end
+
+def end_underline()
+  _ctx.buff.write("\x1b[24m")
+end
+
+def start_hidden()
+  _ctx.buff.write("\x1b[8m")
+end
+
+def end_hidden()
+  _ctx.buff.write("\x1b[28m")
+end
+
+def start_strikethrough()
+  _ctx.buff.write("\x1b[9m")
+end
+
+def end_strikethrough()
+  _ctx.buff.write("\x1b[29m")
+end
+
+def start_color_black()
+  _ctx.buff.write("\x1b[30m")
+end
+
+def end_color_black()
+  _ctx.buff.write("\x1b[40m")
+end
+
+def start_color_red()
+  _ctx.buff.write("\x1b[31m")
+end
+
+def end_color_red()
+  _ctx.buff.write("\x1b[41m")
+end
+
+def start_color_green()
+  _ctx.buff.write("\x1b[32m")
+end
+
+def end_color_green()
+  _ctx.buff.write("\x1b[42m")
+end
+
+def start_color_yellow()
+  _ctx.buff.write("\x1b[33m")
+end
+
+def end_color_yellow()
+  _ctx.buff.write("\x1b[43m")
+end
+
+def start_color_blue()
+  _ctx.buff.write("\x1b[34m")
+end
+
+def end_color_blue()
+  _ctx.buff.write("\x1b[44m")
+end
+
+def start_color_magenta()
+  _ctx.buff.write("\x1b[35m")
+end
+
+def end_color_magenta()
+  _ctx.buff.write("\x1b[45m")
+end
+
+def start_color_cyan()
+  _ctx.buff.write("\x1b[36m")
+end
+
+def end_color_cyan()
+  _ctx.buff.write("\x1b[46m")
+end
+
+def start_color_white()
+  _ctx.buff.write("\x1b[37m")
+end
+
+def end_color_white()
+  _ctx.buff.write("\x1b[47m")
+end
+
+def start_color_default()
+  _ctx.buff.write("\x1b[39m")
+end
+
+def end_color_default()
+  _ctx.buff.write("\x1b[49m")
+end
+
+
+## -------------------------------------------------------------------------
+## TUI MAIN LOOP
+## -------------------------------------------------------------------------
+
+def run(config)
+  term.init(config.capture_events)
+  
+  if config.new_buffer then term.new_screen_buffer() end
+  if config.hide_cursor then hide_cursor() end
+  if config.init_fn then config.init_fn() end
+  
+  event = term.Event()
+  
+  ## The main loop.
+  while not _ctx.done
+    start = clock()
+    
+    ## Dispatch events.
+    while term.read_event(event)
+      if config.event_fn then config.event_fn(event) end
+      if _ctx.done then break end
+    end
+    
+    ## Run frame function
+    if config.frame_fn then config.frame_fn() end
+    
+    ## Sleep to sync FPS.
+    et = clock() - start ## Elapsed time.
+    ft = 1 / config.fps  ## Frame time.
+    
+    ## TODO: set title to print fps if said in config.
+    if ft > et then sleep((ft - et) * 1000) end
+  end
+  
+  ## Cleanup.
+  if config.cleanup_fn then config.cleanup_fn() end
+  if config.hide_cursor then show_cursor() end
+  if config.new_buffer then term.restore_screen_buffer() end
+  term.cleanup()
+  _ctx.clear()
+  
+end

tests/lang/controlflow.pk

@@ -72,6 +72,7 @@ assert(val == 'bar')
 
 
 def test_in_local()
+  x = false
   if x = fn y = false; return not y end ()
     assert(x == true)
   end

tests/modules/io.File.pk

@@ -16,6 +16,7 @@ def read_file()
     'line4 : qux\n',
   ]
 
+  line = ''
   while line = f.getline()
     assert(line in LINES)
   end