| *F was a farmer, and followed the plough.*
.. only:: html
+
.. image:: /images/picE.png
:align: left
#. In that folder, use your text editor to create this source file
``Heidi.inf``:
- .. code-block:: inform6
+ .. code-block:: inform
!% -SD
!============================================================================
Ensure the file is named ``Heidi.inf``, rather than ``Heidi.txt`` or
``Heidi.inf.txt``.
- Remember that, throughout this guide, we place the "TYPE" symbol
+ Remember that, throughout this guide, we place the "``TYPE``" symbol
alongside pieces of code that we recommend you to type into your own
game files as you read through the examples (which, conversely, means
- that you don't need to type the unmarked pieces of code). You'll learn
- Inform more quickly by trying it for yourself, rather than just taking
- our word for how things work.
+ that you *don't* need to type the unmarked pieces of code). You'll
+ learn Inform more quickly by trying it for yourself, rather than just
+ taking our word for how things work.
.. todo::
source. The instructions most commonly placed here are compiler
switches, a way of controlling detailed aspects of how the compiler
operates. These particular switches, two of many, are turning on
- **Strict mode**, which makes the game less likely to misbehave when being
- played, and **Debug mode**, which provides some extra commands which can
- be helpful when tracking down problems.
+ :term:`Strict mode`, which makes the game less likely to misbehave when
+ being played, and :term:`Debug mode`, which provides some extra commands
+ which can be helpful when tracking down problems.
.. note::
line is ignored; if the ``!`` is halfway along a line, the compiler takes
note of the first half, and then ignores the exclamation mark and
everything after it on that line. We call material following an
- exclamation mark, not seen by anybody else, a **comment**; it's often a
- remark that we write to remind ourselves of how something works or why we
- tackled a problem in a particular way. There's nothing special about
+ exclamation mark, not seen by anybody else, a :term:`comment`; it's often
+ a remark that we write to remind ourselves of how something works or why
+ we tackled a problem in a particular way. There's nothing special about
those equals signs: they just produce clear lines across the page.
It's always a good idea to comment code as you write it, for later it
By the way, the compiler *doesn't* give special treatment to exclamation
marks in quoted text: ``!`` within quotes "..." is treated as a normal
character. On this line, the first ``!`` is part of the sequence (or
- string) of characters to be displayed:
+ :term:`string`) of characters to be displayed:
- .. code-block:: inform6
+ .. code-block:: inform
print "Hello world!"; ! <- is the start of this comment
space (except when the spaces are part of a character string). So, these
two rules tell us that we *could* have typed the source file like this:
- .. code-block:: inform6
+ .. code-block:: inform
Constant Story "Heidi";
Constant Headline
you've typed, so it's worthwhile taking a bit of care to make it as
readable as possible.
-* Every game should have the **constant** definitions for ``Story`` (the
- game's name) and ``Headline`` (typically, information on the game's
- theme, copyright, authorship and so on). These two **string** values,
- along with a release number and date, and details of the compiler,
- compose the **banner** which is displayed at the start of each game.
+* Every game should have the :term:`constant` definitions for ``Story``
+ (the game's name) and ``Headline`` (typically, information on the game's
+ theme, copyright, authorship and so on). These two :term:`string`
+ values, along with a release number and date, and details of the
+ compiler, compose the :term:`banner` which is displayed at the start of
+ each game.
* Every game needs the three lines which ``Include`` the standard library
files -- that is, they merge those files' contents into your source file:
- .. code-block:: inform6
+ .. code-block:: inform
Include "Parser";
Include "VerbLib";
- ! ...
+ ...
Include "Grammar";
They always have to be in this order, with ``Parser`` and ``VerbLib``
* Every game needs to define an ``Initialise`` routine (note the British
spelling):
- .. code-block:: inform6
+ .. code-block:: inform
[ Initialise; ];
- The **routine** that we've defined here doesn't do anything useful, but
- it still needs to be present. Later, we'll come back to ``Initialise``
- and explain what a routine is and why we need this one.
+ The :term:`routine` that we've defined here doesn't do anything useful,
+ but it still needs to be present. Later, we'll come back to
+ ``Initialise`` and explain what a routine is and why we need this one.
* You'll notice that each of the items mentioned in the previous three
rules ends with a semicolon. Inform is very fussy about its punctuation,
that's why we were able to take three lines to define the ``Headline``
constant
- .. code-block:: inform6
+ .. code-block:: inform
Constant Headline
"^A simple Inform example
.. image:: /images/heidi1.*
:align: center
-In IF, we talk about each of these locations as a **room**, even though in
-this example none of them has four walls. So let's use Inform to define
+In IF, we talk about each of these locations as a :term:`room`, even though
+in this example none of them has four walls. So let's use Inform to define
those rooms. Here's a first attempt:
-.. code-block:: inform6
+.. code-block:: inform
Object "In front of a cottage"
with description
commonly, that light source is the room itself.
A smidgeon of background may help set this into context (there's more in
-the next chapter). An object can have both **properties** (introduced by
-the keyword ``with``) and **attributes** (written after the word ``has``).
-A property has both a name (like ``description``) and a value (like the
-character string "``You stand outside a cottage. The forest stretches
-east.``"); an attribute has merely a name.
+the next chapter). An object can have both :term:`properties` (introduced
+by the keyword ``with``) and :term:`attributes` (written after the word
+``has``). A property has both a name (like ``description``) and a value
+(like the character string "``You stand outside a cottage. The forest
+stretches east.``"); an attribute has merely a name.
In a little while, when you play this game, you'll observe that it starts
like this:
routes, we also need to explicitly add them to the room definitions in a
form that the game itself can make sense of. Like this:
-.. code-block:: inform6
+.. code-block:: inform
Object before_cottage "In front of a cottage"
with description
[ Initialise; location = before_cottage; ];
-``location`` is a **variable**, part of the library, which tells the
+``location`` is a :term:`variable`, part of the library, which tells the
interpreter in which room the player character currently is. Here, we're
saying that, at the start of the game, the player character is in the
``before_cottage`` room.
with the sketch map until you're comfortable that you understand how to
create simple rooms and define the connections between them.
-.. code-block:: inform6
+.. code-block:: inform
!============================================================================
Constant Story "Heidi";
bird and its nest are Inform objects. We'll start their definitions like
this:
-.. code-block:: inform6
+.. code-block:: inform
Object bird "baby bird"
with description "Too young to fly, the nestling tweets helplessly.",
appropriate to her, with a good chance of it being understood. We add a
line to each definition:
-.. code-block:: inform6
+.. code-block:: inform
Object bird "baby bird"
with description "Too young to fly, the nestling tweets helplessly.",
has ;
The ``name`` introduces a list in single quotes '...'. We call each of
-those quoted things a **dictionary word**, and we do mean "word", not
+those quoted things a :term:`dictionary word`, and we do mean "word", not
"phrase" (``'baby'``\ ``'bird'`` rather than ``'baby bird'``); you can't
-uses spaces, commas or periods in dictionary words, though there's a space
-*between* each one, and the whole list ends with a comma. The idea is that
-the interpreter decides which object a player is talking about by matching
-what she types against the full set of all dictionary words. If the player
-mentions BIRD, or BABY BIRD, or NESTLING, it's the ``baby bird`` that she
-means; if she mentions NEST, BIRD'S NEST or MOSS, it's the ``bird's nest``.
-And if she types NEST BABY or BIRD TWIGS, the interpreter will politely say
-that it doesn't understand what on earth she's talking about.
+uses spaces, commas or periods *in* dictionary words, though there's a
+space *between* each one, and the whole list ends with a comma. The idea
+is that the interpreter decides which object a player is talking about by
+matching what she types against the full set of all dictionary words. If
+the player mentions BIRD, or BABY BIRD, or NESTLING, it's the ``baby bird``
+that she means; if she mentions NEST, BIRD'S NEST or MOSS, it's the
+``bird's nest``. And if she types NEST BABY or BIRD TWIGS, the interpreter
+will politely say that it doesn't understand what on earth she's talking
+about.
.. note::
Furthermore, we label it as ``open``; this prevents the interpreter from
asking us to open it before putting in the bird.
-.. code-block:: inform6
+.. code-block:: inform
Object nest "bird's nest"
with description "The nest is carefully woven of twigs and moss.",
them. Let's say that the bird is found in the forest, while the nest is in
the clearing. This is how we set this up:
-.. code-block:: inform6
+.. code-block:: inform
Object bird "baby bird" forest
with description "Too young to fly, the nestling tweets helplessly.",
they're found. This means adding the bird just after the forest, and the
nest just after the clearing. Here's the middle piece of the source file:
-.. code-block:: inform6
+.. code-block:: inform
!============================================================================
! The game objects
The description of the clearing mentions a tall sycamore tree, up which the
player character supposedly "climbs". We'd better define it:
-.. code-block:: inform6
+.. code-block:: inform
Object tree "tall sycamore tree" clearing
with description
from being picked up by the player character. One final object: the branch
at the top of the tree. Again, not many surprises in this definition:
-.. code-block:: inform6
+.. code-block:: inform
Object branch "wide firm bough" top_of_tree
with description "It's flat enough to support a small object.",
name 'wide' 'firm' 'flat' 'bough' 'branch',
has static supporter;
-The only new things are those two labels. ``static`` is similar to
-``scenery``: it prevents the branch from being picked up by the player
-character, but *doesn't* suppress mention of it when describing the
-setting. And ``supporter`` is rather like the ``container`` that we used
-for the nest, except that this time the player character can put other
-objects *onto* the branch. (In passing, we'll mention that an object can't
-normally be both a ``container`` and a ``supporter``.) And so here are our
-objects again:
+The only new things are those two labels. ``static`` is similar to
+``scenery``: it prevents the branch from being picked up by the player
+character, but *doesn't* suppress mention of it when describing the
+setting. And ``supporter`` is rather like the ``container`` that we
+used for the nest, except that this time the player character can put
+other objects *onto* the branch. (In passing, we'll mention that an
+object can't normally be both a ``container`` *and* a ``supporter``.)
+And so here are our objects again:
-.. code-block:: inform6
+.. code-block:: inform
!============================================================================
! The game objects
put the bird into the nest first. One easy way to enforce this is by
adding a line near the top of the file:
-.. code-block:: inform6
+.. code-block:: inform
!============================================================================
Constant Story "Heidi";
place it on the branch; when that happens, the game should be over. This
is one way of making it happen:
-.. code-block:: inform6
+.. code-block:: inform
Object branch "wide firm bough" top_of_tree
with description "It's flat enough to support a small object.",
projects / ibg.git / blobdiff