27.15. Defining phrases in Inform 6

The phrases described in this documentation, such as "end the story", are all defined in the Standard Rules, and are for the most part defined not in terms of other I7 phrases but instead reduced to equivalents in I6. For instance:

The notation "(-" and "-)" indicates that what comes in between is I6 code. The minus sign is supposed to be a mnemonic for the decrease from 7 to 6: later we shall use "(+" and "+)" to go back up the other way, from 6 to 7.

When a phrase is defined as containing only a single command, and that command is defined using I6 - as here - it is compiled in-line. This means that the phrase "end the story" will always be translated as "deadflag=3; story_complete=false;", rather than being translated into a call to a suitable function whose only statement is "deadflag=3; story_complete=false;".

This is an easy case since the wording never varies. More typical examples would be:

When the braced name of one of the variables in the phrase preamble appears, this is compiled to the corresponding I6 expression at the relevant position in the I6 code. So, for instance,

because "{something}" is expanded to "capacity of the basket" (I7 code) and then translated to "O17_basket.capacity" (I6 code), which is then spliced into the original I6 definition "print {something};".

Braces "{" are of course significant in I6. A real brace can be obtained by making the character following it a space, and then I7 will not attempt to read it as a request for substitution.

It's also possible for the pair of characters "-)" to occur in I6 code, for example here:

and I7 will read the "-)" as terminating the I6; we can get around this with an extra space:

Warning: Inform 6 uses a restricted character set, allowing use of most of the accented characters in ISO Latin-1 (those found in a set called ZSCII) but little beyond that. It's therefore hazardous to use any exotic Unicode characters in an inclusion.

450

ExamplePink or Blue
Asking the player to select a gender to begin play.

Suppose we would like to allow the player to choose a gender for the main character. We'd also like this to happen at the beginning of the game and outside the main parsing sequence. "When play begins" seems like a good place to put this.

"Pink or Blue"

When play begins:
    say "Should your character be male or female? >";
    if men win, now the player is male;
    otherwise now the player is female;
    say paragraph break.

Now a piece of Inform 6 code handles the unusual input. It's not necessary to understand this to use it, and the code should work for any question you'd like to ask the player. The first three words in quotation marks ('male', 'M', 'man'...) correspond to positive feedback; the later three words correspond to negative feedback. So "to decide whether men win" will be true if the player types one of the first three, and false if he types one of the last three.

To decide whether men win:
(- Question('male','M//','man','female','F//','woman') -)

Include (-

[ Question pos1 pos2 pos3 neg1 neg2 neg3 first_word_typed;
    while (true) {
        VM_ReadKeyboard(buffer, parse);
        wn = 1; first_word_typed = NextWordStopped();
        if (first_word_typed == pos1 or pos2 or pos3) rtrue;
        if (first_word_typed == neg1 or neg2 or neg3) rfalse;
        print "Please choose ", (address) pos1, " or ", (address) neg1, ". > ";
    }
];

-)

Instead of examining the player when the player is female:
say "Congratulations, you are a girl!"

Instead of examining the player when the player is male:
say "Congratulations, you are a boy!"

The Room of Self-Knowledge is a room. "Mirrors cover every available wall-surface of this hexagonal chamber, allowing you to examine yourself from all angles."

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