Document how to fix "compiled for target 1.7" error

[manuel-mauky]

When running a small build script like this:

plugins {
    id "org.frege-lang" version "0.8"
}

apply plugin: "java"

dependencies {
    compile "org.frege-lang:frege:3.22.367-g2737683"
    compile "org.frege-lang:fregefx:0.3.1"
}

I get compile errors like this:

E <PATH>/examples/fregefx/src/main/frege/example/fregefx/HelloFrege.fr:7: cannot import fregefx.JavaFxUtils
    compiled for target  1.7 (without lambda support)
    when the current target  1.8 has lambda support
    Try to use compiler option -target 1.7
example.fregefx.HelloFrege: build failed because of compilation errors.

While the error somehow points out what's wrong, I had a hard time finding out how to solve this issue. It seems that there are other users too that have the same error, see Frege/frege#275.

To fix this I've changed my build file like this:

plugins {
    id "org.frege-lang" version "0.8"
}

apply plugin: "java"

compileFrege {
    target = 1.7
}
compileTestFrege {
    target = 1.7
}

dependencies {
    compile "org.frege-lang:frege:3.22.367-g2737683"
    compile "org.frege-lang:fregefx:0.3.1"
}

To lower the hurdle for new users it would be super if this would be documented in the README file.

[manuel-mauky]

Sorry, wrong repository. This issue belongs to https://github.com/Frege/frege-gradle-plugin