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69 lines
3.0 KiB
Plaintext
69 lines
3.0 KiB
Plaintext
(NOTE: view this file with a monospaced font)
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Terminal support in eLua
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================================================================================
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NOTE: currently, this only works over serial connections (not over TCP/IP)
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Besides standard stdio/stdout/stderr support (docs/console_input_output.txt),
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eLua provides the "term" module to access ANSI compatible terminal emulators.
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It is designed to be as flexible as possible, thus allowing a large number of
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terminal emulators to be used.
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To use the term module, remember to:
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- build it (add BUILD_TERM in your build.h file)
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- build its Lua binding ( add AUXLIB_TERM in your platform_libs.h)
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See docs/elua_components.h and docs/platform_modules.txt for details.
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To use it, first call the "term_init" function:
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(BEGIN inc/term.h)
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...........................
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// Terminal output function
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typedef void ( *p_term_out )( u8 );
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// Terminal input function
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typedef int ( *p_term_in )( int );
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// Terminal translate input function
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typedef int ( *p_term_translate )( u8 );
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...........................
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// Terminal initialization
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void term_init( unsigned lines, unsigned cols, p_term_out term_out_func,
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p_term_in term_in_func, p_term_translate term_translate_func );
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(END inc/term.h)
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The initialization function gets the physical size of the terminal emulator
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window (usually 80 lines and 25 cols) and three function pointers:
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- p_term_out: this function will be called to output characters to the terminal.
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It receives the character to output as its single parameter.
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- p_term_in: this function will be called to read a character from the terminal.
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It receives a parameter that can be either TERM_INPUT_DONT_WAIT (in which case
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the function returns -1 immediately if no character is available) or
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TERM_INPUT_WAIT (in which case the function will wait for the character).
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- p_term_translate: this function translates terminal-specific codes to "term"
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codes. The "term" codes are defined in an enum from inc/term.h:
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(BEGIN inc/term.h)
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...........................
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_D( KC_UP ),\
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_D( KC_DOWN ),\
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_D( KC_LEFT ),\
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...........................
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_D( KC_ESC ),\
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_D( KC_UNKNOWN )
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...........................
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(END inc/term.h)
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By using this function, it is possible to adapt a very large number of "term
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emulators" to eLua. For example, you might want to run eLua in a "standalone
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mode" that does not require a PC at all, just an external LCD display and maybe
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a keyboard for data input. Your eLua board can connect to this standalone
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terminal using its I/O pins, for example via SPI. By writing the three functions
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described above, the effort of making eLua work with this new type of device is
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minimal, as writing an "ANSI emulation" for your terminal device is not hard.
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For an example, see src/main.c, where these functions are implemented for an
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UART connection with a terminal emulator program running on PC.
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To see what functions are exported to eLua by the "term" module reffer to the
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"generic_modules.txt" file from the docs/ directory.
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