We have developed a tool, called TV, which shows minimal types of expressions or patterns in Standard ML(SML) programs within the Emacs editor. First, to get the types of expressions or patterns in programs, the programmer executes the programs with TV. Then TV generates files which contain the minimal types of expressions or patterns in the input programs. After having read the programs in the Emacs editor, the programmer can see the types of expressions or patterns with the Emacs functions we have made.
When we understand the SML programs or type errors has been occurred, we need to infer the types of expressions or patterns. The fact that programmers should infer types of them can make understanding SML programs or correcting type errors more difficult, because programmers are prone to making mistakes. TV can be very helpful in such situations.
We have applied TV to various SML programs. TV have showed good performance in storage. To write the type of an expression or pattern, it consumed about 30 bytes per a line.
