it sounds to me like you might be drawing too many parallels between Perl and a truly compiled language such as C/C++, where there are things such as generating a binary and a very clear distinction between compile time and run time.

Perl is not as different as you suggest.

perl compiles Perl code into Perl op codes and operands which are then executed by the Perl virtual machine (PVM).

In theory, the PVM could be implemented in hardware. Many of the Perl op codes correspond to common CPU opcodes. However, the operands are structures. And many of the op codes are more like "system traps" that call a system API function. The PVM is high level machine.

But, it is possible to generate a "binary" file. The Bytecode backend writes Perl bytecode to a file, which the ByteLoader can feed into the PVM.

One of the major problems with this is that if code in BEGIN blocks or in use'd files has "run time side effects", those won't happen when you run the previously compile program.

Bytecode isn't the only option for saving compiled Perl. The Simple C backend encodes Perl's op codes and operands into C source that, when compiled by a C compiler will produce an executable that feeds the compiled Perl code into the PVM. The optimized C backend attempts to de-compile the Perl ops and operands into C code.

But, again, any code in BEGIN blocks or in use'd files won't be run.

If a Perl program is written to have no "run time side effects" at compile time - and only uses modules that are similarly coded, then storing a compiled Perl program in a file for later execution is an option.

In reply to Re^4: What is an ordinary statement? by RonW
in thread What is an ordinary statement? by ntj

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