Skip to content
This repository


Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP

A pathfinding-based esoteric programming language

branch: master

Fetching latest commit…

Cannot retrieve the latest commit at this time


An esoteric programming language that uses pathfinding to determine where the instruction pointer should move next.


Seeker programs consist of a bidirectional graph. Each node holds a single value and can be connected to any number of other nodes. Values are interpreted as opcodes or opcode arguments.

When a Seeker thread has processed the value of its current node, its instruction pointer moves forward - but what is forward in a graph? Seeker uses pathfinding to determine that. Each thread not only keeps track of what node it is currently at, but also what node it is heading for. A thread will always move along the shortest path to its destination.

Quick instructions

To run a .skr file (requires Python 3.x):

python filename.skr

To see all available options:

python -h


The following opcodes are available. Most opcodes take one or more arguments. When an opcode requires arguments, a thread collects the values of subsequent nodes until is the number of arguments is met. The opcode is then executed.

1: set new destination (node id)
2: change connection (node id, node id, 0 or less = disconnect if connected / more than 0 = connect if not connected)
3: change node (node id, 0 or less = destroy if exists / more than 0 = create if not exists)
4: increment node value (node id)
5: decrement node value (node id)
6: copy value from node to node (from node id, to node id)

When Seeker is started in extended mode, the following opcodes become available:

7: create new thread (start node id, destination node id)
8: breakpoint ()

.skr syntax

Seeker programs can be loaded from .skr files. The syntax is quite simple.

To create a node:

node_id : value

To connect two nodes:

node_id - node_id

Node ids and values must be integer numbers. Statements must be separated by non-digit characters (excluding the - and : characters). Nodes can be connected before they have been created - Seeker is smart enough to connect the nodes afterwards.


The following example prints "hello world":

Instruction nodes
0:1     0-1     Set course for node seven
1:7     1-2
2:2     2-3     Disconnect start and end nodes (so the program can terminate instead of backtrack)
3:0     3-4
4:27    4-5
5:0     5-6
6:1     6-7     Set course for end node
7:27    7-8
8:6     8-9     Copy character to following connect/disconnect (to terminate program after printing last character)
9:100   9-10
10:14   10-11
11:2    11-12   Disconnect next point after the last character has been printed, to terminate the program
12:14   12-13
13:15   13-14
14:0    14-15       (character is copied here, if it's zero it disconnects)
15:6    15-16   Print character (copy to IO node)
16:100  16-17
17:0    17-18
18:4    18-19   Increment copy pointer
19:9    19-20
20:4    20-21   Increment print pointer
21:16   21-22
22:2    22-23   Connect start and end nodes again to loop back to the start
23:0    23-24
24:27   24-25
25:1    25-26
26:1    26-27   Set course for the start (just a bit beyond it so the start can set the destination again too)

Data nodes
100: 104    hello world
101: 101
102: 108
103: 108
104: 111
105: 32
106: 119
107: 111
108: 114
109: 108
110: 100
111: 0      Zero terminated string (zero value is used to disconnect nodes, see above)

Which, to Seeker, is the same as:

0:1 0-1 1:7 1-2 2:2 2-3 3:0 3-4 4:27 4-5 5:0 5-6 6:1 6-7 7:27 7-8 8:6 8-9 9:100 9-10 10:14 10-11 11:2 11-12 12:14 12-13 13:15 13-14 14:0 14-15 15:6 15-16 16:100 16-17 17:0 17-18 18:4 18-19 19:9 19-20 20:4 20-21 21:16 21-22 22:2 22-23 23:0 23-24 24:27 24-25 25:1 25-26 26:1 26-27 27:1 100:104 101:101 102:108 103:108 104:111 105:32 106:119 107:111 108:114 109:108 110:100 111:0

TODO: Insert visualization of graph structure as image.


A Seeker programs main thread starts at node number 0 and is heading for node number 1. Without these two nodes, a Seeker program can't start.

Note that node 0 is also the special IO node: copying from this node reads an input byte, or -1 if there is no input. Copying to this node writes the value, converted to a byte, to the output.

If a destination node can be reached through multiple routes of equal length, no guarantees are given as to which route is chosen.

If a thread arrives at it's destination node, it is terminated. Be sure to give threads new destinations to keep them running.

If a thread can't find a route to it's destination node, it stalls. It will only resume when it can find a route again. If all threads in a program are stalled, the program terminates, because then there are no threads left that can unblock other threads by restoring connections between nodes.

Be aware that setting a threads destination might cause it to move 'backwards'. This may cause a thread to process values that were previously used as opcode arguments as opcodes instead (possibly treating the previous opcode as an argument).

Something went wrong with that request. Please try again.