with-open-file

A convenience macro for working on an open file.

Opens a file named name, giving the variable stream to body to perform the stream operations.  It then closes the file when body finishes.  Only the stream variable is visible to body.  Body sees neither name nor parameters.

For example, the below code snippet looks for someone with Dylan in their resume

let line = "";
let dylan-experience = #f;

with-open-file(file = "resume.txt")
  while(line & ~ dylan-experience)
    dylan-experience := regexp-position(line, "dylan");
    line := read-line(file, on-end-of-stream: #f);
  end while;
end;

format-out(if(dylan-experience)
            "Hire this person now!\n"
           else
            "Try someone else\n"
           end if);

Exported from

• Module file-system

Macro call

with-open-file ( (stream) = (locator), (keys) )
  (body)
end

Arguments