Subversion Repositories SvarDOS

                    === SvarCOM implementation notes ===

                    === SvarCOM implementation notes ===

=== SWAPPING =================================================================

=== SWAPPING =================================================================

While conventional RAM is scarce, a command line interpreter must make effort

While conventional RAM is scarce, a command line interpreter must make effort

to reduce its memory footprint when launching applications. SvarCOM does that

to reduce its memory footprint when launching applications. SvarCOM does that

by installing a small executable module in memory, called RMOD (for Resident

by installing a small executable module in memory, called RMOD (for Resident

MODule). SvarCOM pre-sets RMOD so knows how to execute the external program

MODule). SvarCOM pre-sets RMOD so knows how to execute the external program

and removes itself from memory, letting RMOD do the job. RMOD executes the

and removes itself from memory, letting RMOD do the job. RMOD executes the

application, waits for it to finish and then calls back SvarCOM.

application, waits for it to finish and then calls back SvarCOM.

=== NLS STRINGS ==============================================================

=== NLS STRINGS ==============================================================

SvarCOM can output information in many languages. To do so, it relies on a

SvarCOM can output information in many languages. To do so, it relies on a

precompiled resource file named SVARCOM.LNG. When SvarCOM starts, it looks

precompiled resource file named SVARCOM.LNG. When SvarCOM starts, it looks

for this file in the %NLSPATH% directory and loads from it the part that

for this file in the %NLSPATH% directory and loads from it the part that

contains the %LANG% language. All this is done by nls_langreload().

contains the %LANG% language. All this is done by nls_langreload().

The SVARCOM.LNG file is compiled by a separate tool: TLUMACZ. It takes

The SVARCOM.LNG file is compiled by a separate tool: TLUMACZ. It takes

CATS-style language files as input and compiles them into a single SVARCOM.LNG

CATS-style language files as input and compiles them into a single SVARCOM.LNG

resource file. It also produces a DEFAULT.LNG with english strings only, this

resource file. It also produces a DEFAULT.LNG with english strings only, this

one is embedded into the SvarCOM executable to display english text in case

one is embedded into the SvarCOM executable to display english text in case

SVARCOM.LNG is unavailable.

SVARCOM.LNG is unavailable.

=== BATCH FILES SUPPORT ======================================================

=== BATCH FILES SUPPORT ======================================================

When SvarCOM executes a command, it checks first if it has a *.BAT extension.

When SvarCOM executes a command, it checks first if it has a *.BAT extension.

If so, it switches into 'batch-processing' mode:

If so, it switches into 'batch-processing' mode:

 - Writes the batch filename into its persistent (rmod-owned) buffer, along

 - Writes the batch filename into its persistent (rmod-owned) buffer, along

   with a counter that holds the offset of the next line to be executed.

   with a counter that holds the offset of the next line to be executed.

When the batch filename buffer is non-empty, SvarCOM does not ask the user for

When the batch filename buffer is non-empty, SvarCOM does not ask the user for

a command. Instead, it opens the batch file, jumps to the "next line to be

a command. Instead, it opens the batch file, jumps to the "next line to be

executed" and loads the command from there, incrementing the line counter in

executed" and loads the command from there, incrementing the line counter in

the process.

the process.

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