I have installed scala through coursier. Running scala --version in the terminal gives the following:
C:\Users\Me>scala --version
Scala code runner version: 1.4.3
Scala version (default): 3.5.1
When I run scala to start the REPL I get the right welcome. But this REPL seems to be missing commands. :help only returns the following:
Welcome to Scala 3.5.1 (17, Java OpenJDK 64-Bit Server VM).
Type in expressions for evaluation. Or try :help.
scala> :help
The REPL has several commands available:
:help print this summary
:load <path> interpret lines in a file
:quit exit the interpreter
:type <expression> evaluate the type of the given expression
:doc <expression> print the documentation for the given expression
:imports show import history
:reset [options] reset the repl to its initial state, forgetting all session entries
:settings <options> update compiler options, if possible
scala>
And when I run a command not part of this list (such as :kind, the tool I originally wanted to try, mentioned in this answer) it just returns:
scala> :kind x
Unknown command: ":kind", run ":help" for a list of commands
Was there an update to the scala REPL since the answer was posted that removed these commands?
To my understanding, the REPL was more or less fully re-implemented for Scala 3. Various commands were not re-implemented yet, obviously including kind . There's an issue where this is discussed here, but no specific mention of kind there.
What you can do is pass a 2.13.x scala-version to the scala command - that will limit your REPL to that old version of the language, but you would get the full feature set of the old REPL:
% scala --scala-version 2.13
Welcome to Scala 2.13.16 (OpenJDK 64-Bit Server VM, Java 23.0.2).
Type in expressions for evaluation. Or try :help.
scala> :help
All commands can be abbreviated, e.g., :he instead of :help.
:help [command] print this summary or command-specific help
:completions <string> output completions for the given string
:imports [name name ...] show import history, identifying sources of names
:implicits [-v] show the implicits in scope
:javap <path|class> disassemble a file or class name
:line <id>|<line> place line(s) at the end of history
:load <path> interpret lines in a file
:paste [-raw] [path] enter paste mode or paste a file
:power enable power user mode
:quit exit the REPL
:replay [options] reset the REPL and replay all previous commands
:require <path> add a jar to the classpath
:reset [options] reset the REPL to its initial state, forgetting all session entries
:save <path> save replayable session to a file
:sh <command line> run a shell command (result is implicitly => List[String])
:settings <options> update compiler options, if possible; see reset
:silent disable/enable automatic printing of results
:type [-v] <expr> display the type of an expression without evaluating it
:kind [-v] <type> display the kind of a type. see also :help kind
:warnings show the suppressed warnings from the most recent line which had any
Useful default key bindings:
TAB code completion
CTRL-ALT-T show type at cursor, hit again to show code with types/implicits inferred.
scala>