For what it's worth, the ANSI Smalltalk standard says "The protocols specified for literals do not include any messages that modify the state of the literal objects. The effect of sending a message to an object that is the value of a literal that modifies the state of the literal is undefined." This also includes trying to modify an array literal, and fiddling with the bits of a large integer.
That is, according to the ANSI standard, 'abc' is a string but not necessarily a String. I hope that is clear (:-). On Sun, 28 Feb 2021 at 22:57, Sven Van Caekenberghe <s...@stfx.eu> wrote: > Markus, > > 'hello' is a literal string constant, part of the set of constants of a > method (or a doit which like a temporary method disconnected from a class). > > Constants like these are managed by the compiler and can be shared between > different expressions to avoid duplication. > > Changing such a constant is dangerous because it means you are changing > static/compiled code. Consider a method like > > name > ^ 'Markus' > > I could call this method and change the returned string destructively in > place. Next time someone calls it, s/he would get the modified string. Even > worse, s/he would not understand since the source code did not change. > > In the past it was not possible to mark such strings as being constant, > now we can. Which is a big win. > > You can use #copy to get a string that you can modify. > > 'hello' copy at: 2 put: $a; yourself > > HTH, > > Sven > > > On 28 Feb 2021, at 00:50, Markus Wedel <m...@markus-wedel.de> wrote: > > > > Hi all, > > > > strings in Playground are read only in Pharo 9.0 Build 1153 so that > > > > 'hello' at: 2 put: $a; yourself > > ctrl+p > > > > This throws an error: > > „Modification forbidden: ‚hello‘ is read-only, hence its field cannot be > modified with $a > > > > which is actually a very nice error message but is this supposed to > happen? > > The example does work in Pharo 8 without problems. > > > > > > Greetings > > Markus >
