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6.1.2 May 7, 2023
0.2.0 Dec 30, 2018

#176 in Parser implementations

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Used in 2 crates

MIT license


TODO Library

A collection of utilities to work with files in todo.txt format

Working with files

Load todo list

load(filename: &Path) -> Result<TaskVec, terr::TodoError>

Loads a list of todos from a given file path. Returns the list of loaded todos or an error. If the file does not exist the function returns empty list.

Save todo list

save(tasks: &TaskSlice, filename: &Path) -> Result<(), terr::TodoError>

Saves the todo list to a given file path. It may return an error if creating file or writing to it fails. The list is saved in two steps:

  • a list is saved to a temporary file in the same directory with filename
  • on success, it deleted the old file and renames temporary file to filename

Archive completed todos

archive(tasks: &TaskSlice, filename: &Path) -> Result<(), terr::TodoError>

It works similar to save but appends task list to a given filename. It does not create a temporary file.


filter(tasks: &todo::TaskSlice, c: &Conf) -> todo::IDVec

The function gets the list of all todos and filtering rules and returns the list of todo IDs(todo's ID is the order number of the todo in the original list) that matches the rules. If a rule works with strings(e.g, projects or regex), the rule is case-insensitive. Available rules (if a rule is None the rule is skipped):

  • range - selects one todo by its ID, or a few ones within ID range(inclusive), or a list of IDs;
  • all - selects only all done, only incomplete, or both;
  • pri - selects with any priority, without any priority, or with the same/higher/lower priority(inclusive);
  • regex - when use_regex is true, it does regular expression pattern matching, otherwise it search for a substring. Note: it searches for the regex in subject, projects, and contexts;
  • projects - selects all todos that have any of projects. This rule allows a caller to do very basic pattern matching: * added to the beginning or to the end of a project means to look for a project which name ends or starts respectively with the word, Adding * to both ends works like regex but checks only projects. * in the middle of the word does not have any special meaning - use regex in this case;
  • contexts - selects all todos that have any of contexts. The rule can use * in the same way projects does;
  • tags - selects all todos that have any of tags. The rule can use * in the same way projects does;
  • hashtags - selects all todos that have any of hashtags. The rule can use * in the same way projects does;
  • due - selects all todos with any due date, without due date, a todo with due date within range, or todos which are less than the number of days ahead;
  • rec - selects all recurrent todos or all without recurrent flag.
  • thr - selects all todos with any threshold date, without threshold date
  • tmr - selects all active todos - that have their timers running
  • created - selects all todos with any creation date, without creation date, a todo with creation date within range
  • finished - selects all todos with any finish date, without finish date, a todo with finish date within range

Rules contexts, projects, hashtags, and tags support special values:

  • none - filter todos that do not have any values (contexts=['none'] - todos without any context)
  • any - filter todos that have at least one value (project=['any'] - todos that belong to any project)


sort(ids: &mut todo::IDVec, todos: &todo::TaskSlice, c: &Conf)

Because sort is the function that should be called after filter, it wants a list of selected todo IDs that must be sorted, the whole todo list (IDs in ids are the order numbers of a todo in todos) and sorting rules. The function changes ids in-place and the sorting is always stable - it keeps the order of todos in the ids list for todos that are equal to each other. There are only two sorting rules:

  • fields - is a comma(or colon) separated list of fields in order of importance for sorting. If the vector is empty the list remains unchanged. Supported field names(and their abbreviations):
    • pri or priority - sort by priority (without priority are the last ones);
    • due - sort by due date (todos that do not have due date are at the bottom);
    • completed or finished - sort by completion date (incomplete ones are at the bottom);
    • created or create - sort by creation date;
    • subject, subj or text - sort by todo's subjects;
    • done - order: incomplete, recurrent, and done todos;
    • project or proj - sort by project names, if todos have more than one project they are compared in order of appearance and shorter list of projects goes first;
    • context or ctx - sort by contexts, if todos have more than one context they are compared in order of appearance and shorter list of contexts goes first;
    • thr - sort by threshold date (todos that do not have threshold date are at the bottom);
  • rev - when it is true the sorted list is reversed before returning the result.


Add a new todo

add(tasks: &mut TaskVec, c: &Conf) -> usize

The function gets a list of existing todos and a c with non-None field subject, then it parses subject and adds the result todo to the list and return the ID of the new todo. If adding fails - e.g, subject is empty or parsing returns an error - the function returns INVALID_ID.

Modify existing todos

Functions of this category gets a list of all todos, list of todo IDs that should be modified and optionally new values for properties. If list of IDs ids is None then the function modifies all todos. It returns the vector of boolean values with the length equal to the length of ids (or length of tasks if ids is None). If the result vector has true at some index it means that the todo from ids at the same index was modified.

Complete and undone todos

Mark a todo completed

done(tasks: &mut TaskVec, ids: Option<&IDVec>, mode: todotxt::CompletionMode) -> ChangedVec

Makes all todos from ids list that are incomplete completed.

Special case: recurrent todos which contain due date and/or threshold date. They are marked completed, and a new todos are created with their due and threshold dates moved to the next date in the future.

Remove completion mark from a todo

undone(tasks: &mut TaskVec, ids: Option<&IDVec>, mode: todotxt::CompletionMode) -> ChangedVec

Removes completion mark from all todos from ids list that are done.

Special case: recurrent todos. They are not changed.

Changing a specific property

edit(tasks: &mut TaskVec, ids: Option<&IDVec>, c: &Conf) -> ChangedVec

The function modifies all todos in tasks which IDs are in ids list. Note: modifying a subject changes only the first todo in ids list because it does not make sense to make all todos the same.

What can be modified:

  • subject - set a new one
  • priority - set, remove, increase or decrease priority
  • due date - set or remove thresold date - set or remove
  • recurrence - set or remove
  • projects - add, remove or replace
  • contexts - add, remove or replace
  • tags - add, remove or replace
  • hashtags - add, remove or replace

Time tracking support

To calculated time spent on a todo, two main functions are added:

Start and stop time tracking

start(tasks: &mut TaskVec, ids: Option<&IDVec>) -> ChangedVec

Makes todos active if they are incomplete and their is not yet running. All todos saves the timestamp when they were activated.

stop(tasks: &mut TaskVec, ids: Option<&IDVec>) -> ChangedVec

Stop timers for a given todos. Time taken by the todo is updated.

And two utility functions:

is_timer_on(task: &todo_txt::task::Extended) -> bool

Returns true if the given todo is active

spent_time(task: &todo_txt::task::Extended) -> chrono::Duration

Returns the total time spent on the given todo. For an inactive todo it returns the current value of todo's tag spent. For an active todo it returns sum of todo's tag spent and the time passed since the moment the todo was activated.


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