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In Scala REPL one can find value types:
scala> val x = 1
x: Int = 1
scala> :t x
Int
Yet Scala REPL does not show the type information for functions:
scala> def inc(x:Int) = x + 1
inc: (x: Int)Int
scala> :t inc
<console>:9: error: missing arguments for method inc;
follow this method with `_' if you want to treat it as a partially applied function
inc
^
<console>:9: error: missing arguments for method inc;
follow this method with `_' if you want to treat it as a partially applied function
inc
^
How to find function type in Scala REPL ?
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Scala functions are first-class values. Scala functions are first-class values. You must mention the return type of parameters while defining the function and the return type of a function is optional. If you don't specify the return type of a function, the default return type is Unit.
The Scala REPL is a tool (scala) for evaluating expressions in Scala. The scala command will execute a source script by wrapping it in a template and then compiling and executing the resulting program.
The Scala REPL (“Read-Evaluate-Print-Loop”) is a command-line interpreter that you use as a “playground” area to test your Scala code.
We can start Scala REPL by typing scala command in console/terminal.
Following the suggestion will work pretty well:
:t inc _
Int => Int
To give a bit more detail, the reason this is necessary is that Scala maintains a distinction between 'methods', which have native support in the JVM but which are not first class, and 'functions', which are treated as instances of FunctionX and seen as objects by the JVM. The use of the trailing underscore converts the former to the latter.
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