vm3

yet a third

To build and run the example tm in templ.tm:

make templ.tmb
./templ.tmb

Take a look at the file to get an idea of how to write arbitrary turing machines:

# Template Turing Machine definition

# Brief definition of language: (~ means matches regex)
# <empty> ~ /^$/
# <text> ~ /^.*$/
# <int> ~ /^[0-9]*$/
# <ints> := <ints> <int> | <int>
# MaxVert := <int>
# <vert> := 0 < <int> <= MaxVert
# <verts> := <verts> <vert> | <vert>
# <verts?> := <verts> | <empty>
# <op> ~ /^(L|R|X)+$/
#;

# <Name> := Name <text>
# Specify the name of the turing machine in ascii;
Name an example
of a turing machine;

# <Verbose> := Verbose <empty>
# (optional) Specify that the machine should print more output to stdin;
Verbose;

# <Vertices> := Vertices $MaxVert
# Specify the maximum vertex ID. Defines all vertices 1..$MaxVert as valid;
Vertices 3;

# <Tape> := Tape <ints>
# Specify the initial state of the machine tape with an arbitrary list of integers;
Tape 3 1;

# <Start> := Start <vert>
# Specify the start state for the state machine;
Start 1;

# <Accept> := Accept <verts?>
# Specify a list of zero or more accepting states that halt the turing machine;
Accept 2;

# <Reject> := Reject <verts?>
# Specify a list of zero or more rejecting states that halt the turing machine;
Reject;

# <Edge> := Edge <vert> <vert> <int> <int> <op>
# Specify zero or more edges
# NOTE: writing zeros to the tape is not implemented;
Edge 1 1 3 4 R;
Edge 1 2 1 0 L;
Edge 1 3 2 1 R;

# <def> := <Name> | <Verbose> | <Vertices> | <Tape> | <Start> | <Accept> | <Reject> | <Edge>
# <statement> := <def> ;
# <program> := <program> <statement> | <statement>