Updated 2014-05-25 22:57:49 by RLE

Tcl bytecode is the instruction set targeted by TAL

Documentation  edit


Reading  edit


See Also  edit

Parsing, Bytecodes and Execution
Playing bytecode
Brute force meets Goedel
Proc to bytecodes: when, how does it happen
Commands affecting Bytecoding
The anatomy of a bytecoded command
Why compile to bytecode
bytecode dissasembly and/or examination
script compilation

Description  edit

DKF 2003-01-06 (from .NET):

... the current Tcl bytecodes are defined at a level that is meaningful to Tcl, not at a level that virtually any other bytecode operates at; very few bytecodes have an opcode for "increment-hash-entry-and-fire-attached-traces"! Given that, you're either just producing another language reimplementation (like Jacl) or you're taking on the hard task of defining how to go from Tcl to the fairly-common low-level register-based bytecode engines that so many other languages use. Which would be nice and useful, but is a really huge (and definitely complex and deep) task...

Why Byte-Coded Commands Can Be Faster Than C-Coded Commands  edit

Byte-Coded commands are sometimes faster than commands implemented in an external language like C. MS, Tcl Chatroom, 2013-12-31, offered these reasons:

  1. Byte-coded commands access local variables directly, whereas commands implemented in C have to resolve them at runtime.
  2. Dispatch to an external command is slower than dispatch to a byte-coded command
  3. Often, only the most frequently-used code-paths of a command are byte-coded, and corner cases fall back to the C implementation of the command.