Provide default value for build.board.

[damellis]

This preference wasn't required in the boards.txt file previously, so it would be good to generate a default value for it (e.g. the prefix used for that board's keys in boards.txt). (This is for lib-1.5-cores). Otherwise, you get an error like:

 [exec] /Users/mellis/Source/arduino/build/macosx/work/Arduino.app/Contents/Resources/Java/hardware/tools/avr/bin/avr-g++ -c -g -Os -w -fno-exceptions -ffunction-sections -fdata-sections -MMD -mmcu=attiny45 -DF_CPU=1000000L -DARDUINO=153 -D{build.board} -DARDUINO_ARCH_AVR -I/Users/mellis/Source/arduino/build/macosx/work/Arduino.app/Contents/Resources/Java/hardware/arduino/avr/cores/arduino -I/Users/mellis/Documents/Arduino/hardware/attiny/avr/variants/tiny8 /var/folders/v6/4xtyhj9r8xl785006s6n6dkh0000gp/T/build7981273616439051879.tmp/Blink.cpp -o /var/folders/v6/4xtyhj9r8xl785006s6n6dkh0000gp/T/build7981273616439051879.tmp/Blink.cpp.o 
 [exec] <command-line>: error: macro names must be identifiers

[cmaglie]

This build.board is used to obtain a compile time defines like:

ARDUINO_UNO

There is no java code that interacts directly with the "build.board" value, it is a "pure configuration" value.

A solution could be to add a "build.board=ARDUINO_NO_BOARD" into the "arduino" platform.txt as default (specific boards.txt values will override it).

C

[damellis]

Can't we generate a default value like PACKAGE_PLATFORM_BOARDKEY (e.g. ARDUINO_AVR_UNO)? This seems like it would be more consistent and reliable than using arbitrary strings defined by the creator of the boards.txt file.

[cmaglie]

The "boardkey" is defined by the creator of the boards.txt too, I don't see any advantage, just another IDE "feature" to maintain.

[damellis]

That's exactly the point: adding the feature to the IDE (once) instead of making every single author of a boards.txt file add an additional, redundant parameter to the file for every single board they define. We're trying to make it easy for people to add those files. :)

[cmaglie]

I've added a default value as you suggested. BTW, I'd like to have as less magic as possible in the IDE.

The auto-filled define has a side effect: once a core developer choose a board-id he should not touch it anymore, because this can break things on users that have used his previous auto-generated define. I'm not sure that core developers will be aware of that (even if we well document this feature).

Another thing that I dislike is that the auto-filled value becomes implicit, while having it explicitly defined will help 3rd party developers to create plugins, or understand build process.

C