Transition

Rule of thumb: The transitions are handled with the LEFT MOUSE BUTTON

To create a transition press and hold the left button within the origin state, and release it within the destination state

If the transition returns to the same state, then press and hold the left button and release it in the same state. A loop like the one shown below will be created.

NOTE: loops can be resized by dragging the node at the top of the loop up or down.

To delete a transition place the cursor within the transition label, press and hold the RIGHT mouse button (or CTRL & LEFT button) while selecting the desired item in the popup menu, then release the button.

To edit a transition label, press the left button within the label to select it. Then edit its contents using the keyboard. To move to a different field of the label, use the arrow keys or TAB and SHIFT-TAB.

To move a transition label, drag it using the LEFT mouse button. Transition labels can only be moved along the transition itself.

The following is a list of valid characters in transitions while building an automaton.
The comma is only available when creating an FSA and is used as a separator to allow for more than one transition in a label.

NOTE: In grammar conversions it is best to use the lower case letters for the input alphabet and upper case letters for the stack alphabet.

For FSA's:

• Multiple letters can be used at once in a transition.
• A lambda transition is created by simply leaving the contents blank.
• More than one transition can be written in one label by separating them with commas.

For PDA's:

• The symbol representing the empty stack is "Z".
• A PDA label has 3 fields:
  • <input to read> ,
    <string to pop from stack> ;
    <string to push on stack>
  • The transition above would read an "a", pop a "b" from the stack, and push an "A" onto the stack.
    

For 1-Tape Turing machines:

• The B character (capital b) denotes the blank symbol.
• A Turing machine label has 3 fields:
  • <symbol to read> ,
    <symbol to write> ;
    <direction (R, L or S)>
  • The transition above would read an "a" from the tape, write a "c" to the tape, and move the read/write head right.

For 2-Tape Turing machines:

• The B character (capital b) denotes the blank symbol.
• A 2-Tape Turing machine label has 6 fields:
  • <symbol to read from tape 1> ,
    <symbol to write on tape 1> ;
    <direction (R, L or S) on tape 1> |
    <symbol to read from tape 2> ,
    <symbol to write on tape 2> ;
    <direction (R, L or S) on tape 2>
  • The transition above would read an "a" from tape 1, write a "c" to the tape 1, and keep the read/write head for tape 1 in the same place. Also, it would read a "d" from tape 2, write a "e" to the tape 2, and move the read/write head for tape 2 left.