An acrostic is a quote-based word puzzle. It consists of two parts: a grid containing a quote, and a list of clues. Each cell in the grid has a label and corresponds to one of the cells in a clue. The puzzle can be solved by a combination of guessing words in the quote and solving the clues.

Example of a solved acrostic

Entering a guess in either the grid or clue will also guess in its corresponding cell. For example. in the example above, the A at the cursor is being guessed at cell 152A, which is in both the clues and the grid.

As an additional solving aid, the first letter of all the solved clues spells out the title and/or author of the work. This acrostic hint gives the puzzle kind its name. In the example above, the first letter of each answer spells out David Halberstam / The Amateurs, which is the author and title of the work the quote came from.

Representation

Grid

Similar to a crossword, the IpuzCellType is used to determine whether an IpuzCell is a block or guessable. Within a cell, the label and solution fields are used. An IpuzCellType cell could indicate a shaped acrostic, though that is traditionally not used. Similarly, styles are possible but also non-traditional.

There is an IpuzAcrostic:quote property that corresponds to the solution of the grid. This property can be used to provide a user-visible description of the quote. The solution of the grid is constrained to the IpuzPuzzle:charset of the puzzle.

The quote property and grid can be kept in sync with each other through ipuz_acrostic_fix_quote().

Clues

The clues are all of direction IpuzClueDirection. Unlike crosswords, the cells of each clue are not consecutive, but are placed arbitrarily across the grid. When being rendered, the label of the cells of each clue should be extracted from the source clue.

In addition, there is an IpuzAcrostic:source property that corresponds to the first letter of each clue. It spells out the source of the quote — some combination of the author or title.

The source property and clues can be kept in sync with each other through ipuz_acrostic_fix_source().

In addition to the clues, there is a special quote clue that represents the full grid. See ipuz_acrostic_get_quote_clue() for more details.

Guesses

Only IpuzCellType cells are considered with an IpuzGuesses. The string there will be compared to the solution field.

Acrostic puzzles also support using a checksum instead of having a solution.

Editing

The easiest way to create an acrostic is to set the quote and the source, and then use the fix functions to make it work. For example, consider this block:

IpuzPuzzle *acrostic;
const gchar *quote =
  "The time has come, the Walrus said, "
  "To talk of many things: "
  "Of shoes — and ships — and sealing-wax — "
  "Of cabbages — and kings — "
  "And why the sea is boiling hot — "
  "And whether pigs have wings.";
const gchar *source = "Lewis Carroll";

// Note, generating the answers is outside the scope of libipuz
g_autoptr (GArray) answers = generate_answers (quote, source);

acrostic = ipuz_acrostic_new ();
ipuz_acrostic_set_quote (IPUZ_ACROSTIC (acrostic), quote);
ipuz_acrostic_set_source (IPUZ_ACROSTIC (acrostic), source);

// Change the grid to match the quote and label it correctly
ipuz_acrostic_fix_quote (IPUZ_ACROSTIC (acrostic),
                         IPUZ_ACROSTIC_SYNC_STRING_TO_PUZZLE);

// Change the clue count to match the source
ipuz_acrostic_fix_source (IPUZ_ACROSTIC (acrostic),
                          IPUZ_ACROSTIC_SYNC_STRING_TO_PUZZLE);

// Set answers to all clues. Answers is a GArray of strings,
// collectively containing each letter in quote
ipuz_acrostic_set_answers (IPUZ_ACROSTIC (acrostic), answers);

// update the labels to match the clues
ipuz_acrostic_fix_labels (IPUZ_ACROSTIC (acrostic));

This will generate the following grid:

Grid generated by the code example