2025-07-10: Fuzion July Update

Last month brought some nice language improvements for destructuring, nullary functions and automatic unwrapping and a number of enhancements in the base library and bug fixes and cleanup in the tools.

• General

  • Within the GreenCode project, we have started collecting requirements for realtime APIs including features to monitor resource usage and enforce limits.

• Fuzion language

  • Field declaration now supports destructuring simplifying the grammar and the code (#5173)

    To destructure a complex number, you can now write

    c := num.complex 1 2
    
    re, im := c*c
              

    Using parentheses is no longer needed but also no longer allowed

    (re, im) := c*c    # *** no longer supported, causes error
              

    Initialization of several fields using a tuple requires parentheses only on the right hand side:

    one, two, three := (1, 2, 3)
              

  • Support type inference for nullary lambda expressions, fix #1015 (#5308)

    So, we no longer need to specify a type in declarations like this:

    f := () -> say "hello"
    f.call
                

  • auto unwrap target of call if necessary (#5362)

    This permits code like the following without explicitly unwrapping mutable variables

      a := mut.new 3
      b := mut.new 4
      say a+b
                

• Base library

  • New library features

    • process.send_signal (#5351)

    • switch.or_cause, unwrap or cause exception (#5322)

    • add Sequence.is_sorted (#5383)

    • add unit-type feature realtime as the basis for realtime APIs (#5356)

    • tuple: add tuple1, tuple2 etc. for creating tuples (#5385)

      These are convenient, e.g., to zip Sequences as in

      a.zip b tuple2
                  

      instead of

      a.zip b x,y->(x,y)
                  

    • modules: add json_encode (#5350)

    • lib: define writer.finally to flush when deinstating effect (#5319)

  • Changed library features

    • fix precondition of container.ordered_map (#5386)

    • improve error messages in fuzion.sys.fileio (#5340)

    • net, improve error messages (#5357)

    • rename effect0 as effect_to_be_instated (#5387)

    • rename handle0/handle2_0 as handle_id/handle2_id (#5388)

    • define mutate local to file, change file.use to use it (#5286)

    • list.as_string, syntax simplification (#5349)

    • total order of complex numbers now takes imaginary part into account (#5336)

  • Removed library features

    • remove choice.type.tag, we can use id instead, e.g., id (option String) "abc" instead of (option String).tag "abc" (#5344)

    • remove envir.vars.get (#5355)

    • In Sequence, removed infix operators !, |& and & to avoid cryptic code. for_each and filter can be used instead (#5327)

• Parser

  • better source range for errors involving anonymous features (#5424)

  • in loop, use position of else for better error reporting (#5396)

• Front end

  • AbstractAssign, checkTypes, check for direct assignability since tagging / boxing is already done at this point (#5376)

  • AbstractFeature, cache selfType (#5421)

  • InlineArray, fix target type (#5400)

  • change AbstractType.toString for this-types: now instead of a.this.b.this, print just a.b.this (#5412)

  • error on mismatch of destructured and available argument fields (#5381)

  • explicitly specify if innerFixed in some places (#5420)

  • fix resultTypeIfPresentUrgent for outer ref (#5414)

  • fix handling of open type parameters when resolving types (#5439)

  • fix require-condition when generic sizes don't match (#5347)

  • move resolvedFormalArgumentTypes from Call to AbstractCall (#5432)

  • throw error on calling UnresolvedType.asValue (#5426)

  • isAssignable return YesNo instead of bool enabling suppression of subsequent errors(#5338)

  • fix IndexOutOfBoundsException (#5404)

  • change AbstractType.isAssignable to handle tagging/boxing (#5298)

  • In Tag, move checkChoice to checkTypes phase (#5373)

• DFA

  • implement comparison of SysArray (#5438)

• FUIR

  • fix Clazz.findOuter (#5304)

• JVM back end

  • fix verify error for unreachable code (#5379)

  • improve error message for missing library libfuzion_rt.so (#5348)

• Windows

  • fix windows build (#5371)

• Documentation

  • fix asciidoc code for Match entry in fum file (#5406)

  • in API docs: improve alignment in feature list (#5390)

  • fix links of base module feature displayed in other modules (#5403)

  • fix missing comments in API docs (#5392)

  • for function features hide inner (inherited) functions and fields (#5389)

  • require leading blank line for code blocks in comments (#5393)

• Tests

  • tests: add output to compile.mk/fe.mk (#5329)

• Examples

  • add test for pkg-config and gtk, documentation (#5380)

Cheers,

--The Fuzion Team.