ref: 698823e14ffa769229315317298337cbcd3f64d1
dir: /README.md/
# todo2
This simple script makes us of directed acyclic graph solving, to express TODO lists in a way that allows multiple hierarchies of parent/child relationships between different atomic tasks.
Consider the following traditional TODO list.
```
# Birthday Party TODO
[ ] eat cake
[ ] blow out candles
[ ] give presents
```
Normally, the other steps involved in making the above happen would be listed; perhaps even heirarchally:
```
# Birthday Party TODO
[ ] Get cake mix
[ ] Bake cake
[ ] Eat cake
[ ] Buy candles
[ ] Light candles
[ ] Blow out candles
[ ] Buy presents
[ ] Wrap presents
[ ] Give presents
```
Generally, that's enough for many tasks. But in the programming world, we develop hierarchies of things where multiple pieces, may depend on multiple, disperate pieces; a flat hierarchy doesn't suffice.
Now, many other methods use tagging to achieve this:
```
# Big project
[ ] Fix bug #92930
[ ] Ship update #3
[ ] Fix bug #01209
[ ] Ship update #3
```
This works wonderfully well, but it is not robust enough for multiple parent, multiple child relationships that may arise in real life. If Fix #92930 depends on 3 other things, one of which depends on #01209 we wouldn't be able to express that #01209 blocks the parent dependencies of #92930 cleanly.
Make solves these sort of dependency hierarchies cleanly, and since I didn't want to write a solver itself at this time, why not just use it!
## .todo files
A .todo file contains a checklist of items to complete an atomic task. For example, `polygon.todo` may contain the following:
```
BUG #92930 - Trying to seek returns incomprehensible error when calling SomeCall
[ ] polygon.go: MyType should implement ReaderAt
[ ] polygon.go: Check return value of SomeCall and try to recover
[ ] polygon.go: Hand back better error info to the calling function
BUG #012099 - Blob considered too small by users
[ ] blob.go: Make blob 2x larger when it feels threatened
[ ] blob.go: Implement room bounds checking
```
To add an entry into a particular task, such as the last line of BUG #92930 is trivial:
`todo add entry 'BUG #92930' "polygon.go: Hand back better error info to the calling function"`
You can also use stdin:
`some function | todo add entry someentry`
If for some reason you wish to remove an entry, you can use the complement to `add`, `rm`.
`todo remove entry 'BUG #92930'`
Since .todo files are simply text files, you can also achieve any of the above by opening and editing the file by hand.
## Completing tasks in .todo files
The following commands modify the state of a given entry's task:
- `todo task toggle <entry> <index|string>`
- `todo task rm <entry> <index|string>`
For example, to toggle the completion of MyType implementing ReaderAt:
`todo task toggle 'BUG #92930' 'MyType should implement ReaderAt'`
You'll notice the file name is elided, for brevity a partial string match is all that is required. `todo task toggle 'BUG #92930' MyType` would suffice in our example.
By index, it's similar: `todo task toggle 'BUG #92930' 1` would update the .todo file to read `[x] polygon.go: MyType should implement ReaderAt`.
## Automatically generate .todo files
Now, no one wants to write all that out all the time. Shouldn't this be able to pull a generic `// TODO:` tag, or `# TODO:`, etc? Yeah, I thought so too.
`todo generate` will walk the source tree, looking `TODO`, `BUG`, `RELEASE`, and other related tags. If they have a tag, such as `BUG #92930: Trying to seek returns incomprehensible error when calling SomeCall` an entry will be made in an appropriate .todo file in that particular source directory/subdirectory, which will be created as necessary.
- files with extensions will have the extension replaced with .todo, and files without extensions will gain the extension .todo. Name collisions should be benign here.
- more extensive coverage of tagging conventions can be Pull Requested as needed by users
## Managing dependancy hierarchy
`todo add` is the base command we'll be using, to add hierarchies. (A complementary `todo rm` can be used to undo anything `todo add` can do!)
To add something as a child dependency, `todo add child <parent name> <child name>`. From the above examples, you would issue `todo add child 'BUG #01209' 'BUG #92930'`, or equivilently `todo add parent 'BUG #92930' 'BUG #01209'`.
Arbitrarily many dependencies can be added between arbitrary pieces within the current working source tree.
## Commands of intrigue
- `todo init` will create, if none exists, the backing Makefile-like file used internally
- `todo list` will output a list of all current leaves in the graph, (nodes which have no pending dependencies)
- `todo listall` will list every piece of the graph in a flat structure. This is very useful in defining hierarchies on complicated TODO list
- `todo dot` can be piped to `graphviz` and friends to view your current task hierarchies, with the completed nodes elided
- `todo dotall` will output a complete graph of all task hierarchies
## Sharing
The best method is to include your existing todo2 main file into your current revision system, and symbolically link it into the `$XDG_DATA_HOME/todo2/myproject` directory.