Pas2js optimizations

Overview

This page describes existing optimizations for the pas2js transpiler as well as feature requests.

Generated JavaScript

Existing optimizations

• -O-: Disable all optimizations
• -O1 : Level 1 optimizations (quick and debugger friendly)
• -OoEnumNumbers[-]: write enum value as number instead of name. Default in -O1.
• -OoRemoveNotUsedPrivates[-]: Default is enabled
• -OoRemoveNotUsedDeclarations[-]: Default enabled for programs with -Jc
• omit unneeded brackets in associative operations (a||b)||(c||d), (a&&b)&&(c&&d), (a|b)|c, (a&b)&c, (a^b)^c, (a+b)+c, (a-b)-c, (a*b)*c

Feature requests

• -O2 : Level 2 optimizations, slow and not debugger friendly
• -O3 : Level 3 optimizations, slow and might break special code

Compiler itself

The compiler was deliberately written

• in a modular fashion. Each part has its own test suite and is used by other projects.
• can be used in a library, i.e. no restart required to compile another program.
• can be used without a filesystem, i.e. in a browser
• threadsafe, i.e. the compilation can run in a thread. Compiling a program with multiple threads is planned.
• easy maintenance has higher priority than high speed and low memory