This simple library builds valid mu find queries from simple and idiomatic S-expression forms.

For instance:

ELISP> (mu4e-make-query
 '(and
   (subject "Your Festivus Catalogue is on its way!")
   (to "costanza@example.com")))
"(subject:\"Your Festivus Catalogue is on its way!\" and to:costanza@example.com)"

Instead of wrangling strings, you can build your queries freely using variables and nested forms to meet your needs.

Here's an example that configures mu4e-bookmarks:

(setq mu4e-bookmarks `((:name "Shared inbox"
                        :query ,(mp-mu4e-make-query
                                 '(and (not (flag trashed)) (maildir (regex "Inbox$"))))
                        :key ?i))

All known features of mu find are supported, including:

• Automatic quoting when white spaces are used

• Support for free-form searches

• String fallback if you want to mix S-expressions and mu queries

• Full support for all flags and fields, including shorthands and aliases

• Range queries (for date and size) are also supported

• Several helper forms that simplify query building, including (rx ...) for Emacsy regex generation

• and (one-of ...) and (all-of ...) forms that generate logical or or and queries for a field, to speed up query writing:

  ELISP> (mu4e-make-query '(contact (one-of "kramer" "costanza" "seinfeld" "benes")))
  "(contact:kramer or contact:costanza or contact:seinfeld or contact:benes)"

Install this module somewhere then require it, and call mu4e-make-query. See its docstring (or the commentary in mu4e-query.el) for more information.

Both shorthands -- like f, b, p, etc. -- and their longform field names work.

You can express flags with either their long-form or shorthand names also. Date and size ranges also work.

Fields and flags work the same way. They're specified as (flag ...) or (subject ...). E.g.:

(flag seen)
(maildir "/foo")
(size ("1M" .. "1G"))

Range queries work the same way but require a cons to match:

ELISP> (mu4e-make-query '(size (1M .. 1G)))
"size:1M..1G"
ELISP> (mu4e-make-query '(date ( .. 1w)))
"date:..1w"

The (regex ...) form generates an ed-style regex:

ELISP> (mu4e-make-query '(from (regex "[FG] Costanza")))
"from:/[FG] Costanza/"

But you can also use Emacs's excellent rx package to generate complex regex patterns. Note, though, that mu does not use Emacs's regex engine, so there are differences:

ELISP> (mu4e-make-query '(from (rx (| "George" "Frank"))))
"from:/\\(?:Frank\\|George\\)/"

Instead of repeating yourself if you have a range of fields that must match one or -- or all of -- a set of a values, you can use the helper forms (one-of ...) and (all-of ...) instead:

ELISP> (mu4e-make-query '(from (one-of "elaine benez" "cosmo kramer")))
"(from:\"elaine benez\" or from:\"cosmo kramer\")"