Metacommand: Difference between revisions

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==Legacy Metacommands (QBasic/QuickBASIC)==
== Legacy Metacommands (QBasic/QuickBASIC) ==
:*Legacy metacommands are normally used at the program start, they should have their own program line and must be commented with an ''[[Apostrophe|']]'' or [[REM]].
:*Legacy metacommands are normally used at the program start, they should have their own program line and must be commented with an ''[[Apostrophe|']]'' or [[REM]].
* [[$DYNAMIC]] {{Text|set all program arrays as changeable in size using [[REDIM]].}}
* [[$DYNAMIC]] {{Text|set all program arrays as changeable in size using [[REDIM]].}}
* [[$INCLUDE]] {{Text|designates a text code library file to include with the program.}}
* [[$INCLUDE]] {{Text|designates a text code library file to include with the program.}}
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==QB64 Metacommands==
== QB64 Metacommands ==
:*QB64 metacommands must not necessarily used at the program start. However, it's still the best location for some of it (see individual descriptions).
:*QB64 metacommands must not necessarily used at the program start. However, it's still the best location for some of it (see individual descriptions).
:*QB64 metacommands must not be commented with an ''[[Apostrophe|']]'' or [[REM]], but should have their own program line too.
:*QB64 metacommands must not be commented with an ''[[Apostrophe|']]'' or [[REM]], but should have their own program line too.
* [[$ASSERTS]] {{Text|enables debug tests with the [[_ASSERT]] macro.}}
* [[$ASSERTS]] {{Text|enables debug tests with the [[_ASSERT]] macro.}}
* [[$CHECKING]] {{Text|turns event and error checking OFF or ON.}}
* [[$CHECKING]] {{Text|turns event and error checking OFF or ON.}}
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==OB64 Precompiler Commands==
== OB64 Precompiler Commands ==
:*These are a special type of ''{{Text|QB64 Metacommands|blue}}'', which allow for conditional compiling, hence including or excluding certain code sections depending on given conditions.
:*These are a special type of ''{{Text|QB64 Metacommands|blue}}'', which allow for conditional compiling, hence including or excluding certain code sections depending on given conditions.
* [[$ELSE]] {{Text|used in conjunction with [[$IF]] for the precompiler.}}
* [[$ELSE]] {{Text|used in conjunction with [[$IF]] for the precompiler.}}
* [[$ELSEIF]] {{Text|used in conjunction with [[$IF]] for the precompiler.}}
* [[$ELSEIF]] {{Text|used in conjunction with [[$IF]] for the precompiler.}}
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==See also==
{{PageSeeAlso}}
* [[Statement]], [[Sub (explanatory)]]
* [[Statement]], [[Sub (explanatory)]]
* [[Function (explanatory)]]
* [[Function (explanatory)]]

Revision as of 22:25, 28 July 2022

Metacommands are commands that start with dollar sign ($). Those commands usually switch the program between different operation modes/behavior or provide extended functionality.


Legacy Metacommands (QBasic/QuickBASIC)

  • Legacy metacommands are normally used at the program start, they should have their own program line and must be commented with an ' or REM.
  • $DYNAMIC set all program arrays as changeable in size using REDIM.
  • $INCLUDE designates a text code library file to include with the program.
  • $STATIC set all program arrays as unchangeable in size using DIM.


QB64 Metacommands

  • QB64 metacommands must not necessarily used at the program start. However, it's still the best location for some of it (see individual descriptions).
  • QB64 metacommands must not be commented with an ' or REM, but should have their own program line too.
  • $ASSERTS enables debug tests with the _ASSERT macro.
  • $CHECKING turns event and error checking OFF or ON.
  • $COLOR includes named color name constants in a program.
  • $CONSOLE creates a console window that can be used throughout a program.
  • $DEBUG enables debugging features, allowing you to step through your code line by line.
  • $EXEICON used with a .ICO icon file name to embed the image into the QB64 executable.
  • $NOPREFIX allows QB64-specific keywords to be used without the underscore prefix.
  • $RESIZE used with ON allows a user to resize the program window where OFF does not.
  • $SCREENHIDE hides the program window from view.
  • $SCREENSHOW displays the program window after it was hidden.
  • $VERSIONINFO adds metadata to Windows only binaries for identification purposes across the OS.
  • $VIRTUALKEYBOARD (deprecated) turned the virtual keyboard ON or OFF for use in touch-enabled devices.


OB64 Precompiler Commands

  • These are a special type of QB64 Metacommands, which allow for conditional compiling, hence including or excluding certain code sections depending on given conditions.
  • $ELSE used in conjunction with $IF for the precompiler.
  • $ELSEIF used in conjunction with $IF for the precompiler.
  • $END IF used in conjunction with $IF for the precompiler.
  • $ERROR used to trigger compiler errors from within the precompiling pass.
  • $IF used to set an IF condition for the precompiler.
  • $LET used to set a variable for the precompiler.


See also



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