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diff --git a/doc/limitations.md b/doc/limitations.md index 92858cb1f..265e4a2d4 100644 --- a/doc/limitations.md +++ b/doc/limitations.md @@ -13,40 +13,9 @@ This document is collecting these limitations. This document does not contain a complete list of limitations. Please help to improve it by submitting your findings. +## `Kernel.raise` in rescue clause -## ```1/2``` gives ```0.5``` - -Since mruby does not have ```Bignum```, bigger integers are represented -by ```Float``` numbers. To enhance interoperability between ```Fixnum``` -and ```Float```, mruby provides ```Float#upto``` and other iterating -methods for the ```Float``` class. As a side effect, ```1/2``` gives ```0.5``` -not ```0```. - -## ```Array``` passed to ```puts``` - -Passing an Array to ```puts``` results in different output. - -```ruby -puts [1,2,3] -``` - -#### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] - -``` -1 -2 -3 -``` - -#### mruby [1.4.1 (2018-4-27)] - -``` -[1, 2, 3] -``` - -## ```Kernel.raise``` in rescue clause - -```Kernel.raise``` without arguments does not raise the current exception within +`Kernel.raise` without arguments does not raise the current exception within a rescue clause. ```ruby @@ -59,26 +28,34 @@ end #### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] -```ZeroDivisionError``` is raised. +`ZeroDivisionError` is raised. -#### mruby [1.4.1 (2018-4-27)] +#### mruby [3.0.0 (2021-03-05)] -No exception is raised. +`RuntimeError` is raised instead of `ZeroDivisionError`. To re-raise the exception, you have to do: + +```ruby +begin + 1 / 0 +rescue => e + raise e +end +``` ## Fiber execution can't cross C function boundary -mruby's ```Fiber``` is implemented in a similar way to Lua's co-routine. This +mruby's `Fiber` is implemented similarly to Lua's co-routine. This results in the consequence that you can't switch context within C functions. -Only exception is ```mrb_fiber_yield``` at return. +Only exception is `mrb_fiber_yield` at return. -## ```Array``` does not support instance variables +## `Array` does not support instance variables -To reduce memory consumption ```Array``` does not support instance variables. +To reduce memory consumption `Array` does not support instance variables. ```ruby class Liste < Array def initialize(str = nil) - @feld = str + @field = str end end @@ -87,16 +64,16 @@ p Liste.new "foobar" #### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] -``` [] ``` +` [] ` -#### mruby [1.4.1 (2018-4-27)] +#### mruby [3.0.0 (2021-03-05)] -```ArgumentError``` is raised. +`ArgumentError` is raised. ## Method visibility For simplicity reasons no method visibility (public/private/protected) is -supported. +supported. Those methods are defined, but they are dummy methods. ```ruby class VisibleTest @@ -119,17 +96,53 @@ false true ``` -#### mruby [1.4.1 (2018-4-27)] +#### mruby [3.0.0 (2021-03-05)] ``` true true ``` -## defined? +### Visibility Declaration -The ```defined?``` keyword is considered too complex to be fully -implemented. It is recommended to use ```const_defined?``` and +The declaration form of following visibility methods are not implemented. + +* `public` +* `private` +* `protected` +* `module_function` + +Especially, `module_function` method is not dummy, but no declaration form. + +``` +module TestModule + module_function + def test_func + p 'test_func called' + end + + test_func +end + +p 'ok' +``` + +#### Ruby [ruby 2.5.5p157 (2019-03-15 revision 67260)] + +``` +ok +``` + +#### mruby [3.0.0 (2021-03-05)] + +``` +test.rb:8: undefined method 'test_func' (NoMethodError) +``` + +## `defined?` + +The `defined?` keyword is considered too complex to be fully +implemented. It is recommended to use `const_defined?` and other reflection methods instead. ```ruby @@ -142,11 +155,11 @@ defined?(Foo) nil ``` -#### mruby [1.4.1 (2018-4-27)] +#### mruby [3.0.0 (2021-03-05)] -```NameError``` is raised. +`NameError` is raised. -## ```alias``` on global variables +## `alias` on global variables Aliasing a global variable works in CRuby but is not part of the ISO standard. @@ -157,9 +170,9 @@ alias $a $__a__ #### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] -``` nil ``` +` nil ` -#### mruby [1.4.1 (2018-4-27)] +#### mruby [3.0.0 (2021-03-05)] Syntax error @@ -178,15 +191,15 @@ end #### Ruby [ruby 2.0.0p645 (2015-04-13 revision 50299)] -```ArgumentError``` is raised. -The re-defined ```+``` operator does not accept any arguments. +`ArgumentError` is raised. +The re-defined `+` operator does not accept any arguments. -#### mruby [1.4.1 (2018-4-27)] +#### mruby [3.0.0 (2021-03-05)] -``` 'ab' ``` +` 'ab' ` Behavior of the operator wasn't changed. -## Kernel#binding is not supported +## `Kernel#binding` is not supported `Kernel#binding` method is not supported. @@ -197,7 +210,7 @@ $ ruby -e 'puts Proc.new {}.binding' #<Binding:0x00000e9deabb9950> ``` -#### mruby [1.4.1 (2018-4-27)] +#### mruby [3.0.0 (2021-03-05)] ``` $ ./bin/mruby -e 'puts Proc.new {}.binding' @@ -209,8 +222,7 @@ trace (most recent call last): ## Keyword arguments mruby keyword arguments behave slightly different from CRuby 2.5 -to make the behavior simpler and less confusing. Maybe in the -future, the simpler behavior will be adopted to CRuby as well. +to make the behavior simpler and less confusing. #### Ruby [ruby 2.5.1p57 (2018-03-29 revision 63029)] @@ -219,7 +231,7 @@ $ ruby -e 'def m(*r,**k) p [r,k] end; m("a"=>1,:b=>2)' [[{"a"=>1}], {:b=>2}] ``` -#### mruby [] +#### mruby [3.0.0 (2021-03-05)] ``` $ ./bin/mruby -e 'def m(*r,**k) p [r,k] end; m("a"=>1,:b=>2)' @@ -227,3 +239,38 @@ trace (most recent call last): [0] -e:1 -e:1: keyword argument hash with non symbol keys (ArgumentError) ``` + +## `nil?` redefinition in conditional expressions + +Redefinition of `nil?` is ignored in conditional expressions. + +```ruby +a = "a" +def a.nil? + true +end +puts(a.nil? ? "truthy" : "falsy") +``` + +Ruby outputs `falsy`. mruby outputs `truthy`. + +## Argument Destructuring + +```ruby +def m(a,(b,c),d); p [a,b,c,d]; end +m(1,[2,3],4) # => [1,2,3,4] +``` + +Destructured arguments (`b` and `c` in above example) cannot be accessed +from the default expression of optional arguments and keyword arguments, +since actual assignment is done after the evaluation of those default +expressions. Thus: + +```ruby +def f(a,(b,c),d=b) + p [a,b,c,d] +end +f(1,[2,3]) +``` + +CRuby gives `[1,2,3,nil]`. mruby raises `NoMethodError` for `b`. |