Ctrl-C: Handles sigint much more elegantly

src/fsh.nim

@@ -35,6 +35,7 @@ type
     variable: string
   ShellCommandError = object of ShellError
     command: string
+  InterruptCtrlC = object of CatchableError
 
 # procs for making procedures
 proc newShellException(msg: string, line=0, col=0, whileExec=""): ref ShellError =
@@ -64,6 +65,10 @@ proc newShellCommandException(msg: string, command: string, line=0, col=0, while
 proc eval(cmd: string): string
 proc substitute(strm: Stream, delim = ";\p"): string
 
+# ctrlc is the ctrl-c handler
+proc ctrlc() {.noconv.} =
+  raise newException(InterruptCtrlC, "")
+
 # skipSpaces reads the stream until a non-space character is found
 proc skipSpaces(strm: Stream): int =
   while not strm.atEnd():
@@ -321,6 +326,14 @@ proc eval(cmd: string): string =
   strm.close
 
 when isMainModule:
+  # ctrlc handler
+  setControlCHook(ctrlc)
   let stdinstrm = stdin.newFileStream
   while not stdinstrm.atEnd():
-    stdinstrm.readCommand.execute.echo
+    try:
+      discard stdinstrm.readCommand.execute
+    except ShellError, ShellCommandError, ShellVariableError:
+      let e = getCurrentException()
+      stderr.write(e.msg, "\n")
+    except InterruptCtrlC:
+      continue