fsharp/fsharp — pull request #281 by enricosada (2014-03-02 21:53:05+00:00)
Title: help first time users of fsi

fix #92

with FSI:
help command is `#help;;`
quit command is `#quit;;`

but first time users maybe try instead `help;;` `quit;;` `exit;;` `#exit;;`

This commit add eval of:
* `quit;;` or `exit;;` ( without # ) show, after eval result, the
howto quit help message
* `help;;` show, after eval result, the help message
* `#exit;;` show, after invalid directive message, the howto quit
message

On mono, the quit help message write `Ctrl-D` instead of `Ctrl-Z`

examples:
```
> quit;;

quit;;
^^^^

stdin(1,1): error FS0039: The value or constructor 'quit' is not defined
Use #quit;; or Ctrl-Z to exit
```
```
> exit;;
val it : (int -> 'a) =
Use #quit;; or Ctrl-Z to exit
```
```
> #exit;;
Invalid directive '#exit '
Use #quit;; or Ctrl-Z to exit
```
```
> help;;

help;;
^^^^

stdin(4,1): error FS0039: The value or constructor 'help' is not defined

F# Interactive directives:

#r "file.dll";; Reference (dynamically load) the given DLL
#I "path";; Add the given search path for referenced DLLs
#load "file.fs" ...;; Load the given file(s) as if compiled and referenced
#time ["on"|"off"];; Toggle timing on/off
#help;; Display help
#quit;; Exit

F# Interactive command line options:

See 'fsi --help' for options
```