- The Inform 7 compiler
§1. The task of the Inform 7 compiler is to take source text which may be as minimal as "The Taj Mahal is a room.", and to turn it into a computer program. It is properly speaking a "transpiler", in that it compiles down to code for another compiler to take the rest of the way. Traditionally, that other compiler is Inform 6 (1996-2003), a reliable generator of "story files" (programs for virtual machines) from typeless but otherwise C-like code.
The Inform 7 compiler works in three phases:
- (1) A build manager reads in the text, breaks it into sentences, finds the necessary extensions, merges them in, and generally decides what to do.
- (2) The core of the compiler translates this assemblage of source text into a low-level abstract language called "inter".
- (3) The code-generator further translates that intermediate code into our final output, which will be code for some lower-level compiler.
§2. Three ccmmand-line tools are provided: inbuild, inform7, and inter.
They roughly correspond to the three phases, but inbuild can also
perform some useful archiving and resource management functions, and inter
can also perform assimilation on kits, or translate inter code not originated by
Inform. inform7 on its own is capable of performing the complete compilation
process and is the only one of the three included in the GUI apps of Inform
for MacOS, Windows and so on.
Each tool has a tiny CLI (or "command-line interface") but is otherwise
divided up into large segments called "modules", many shared between two or
even all three tools. inform7 contains every module. The following diagram
shows exactly how:
+-------------+ +-------------+ +-------------+
| INBUILD | | INFORM7 | | INTER |
| | | | | |
+---+.............+---+ +---+.............+---+ +---+.............+---+
| inbuild (cli shell) | | inform7 (cli shell) | | inter (cli shell) |
+---+.............+---+ +---+.............+---+ +---+.............+---+
| | | | | |
+---+.............+----------+.............+---+ | |
| inbuild-module | | |
| syntax-module | | |
| html-module | | |
+---+.............+----------+.............+---+ | |
| | | | | |
| | +---+.............+---+ | |
| | | core-module | | |
| | | inflections-module | | |
| | | linguistics-module | | |
| | | problems-module | | |
| | | kinds-module | | |
| | | if-module | | |
| | | multimedia-module | | |
| | | index-module | | |
| | +---+.............+---+ | |
| | | | | |
| | +---+.............+----------+.............+---+
| | | inter-module |
| | | building-module |
| | | codegen-module |
| | +---+.............+----------+.............+---+
| | | | | |
+---+.............+----------+.............+----------+.............+---+
| words-module |
| arch-module |
+---+.............+----------+.............+----------+.............+---+
| | | | | |
+---+.............+----------+.............+----------+.............+---+
| (foundation-module from inweb) |
| (Posix or Windows-related functions) |
| (standard C library) |
+---+.............+----------+.............+----------+.............+---+
| | | | | |
+-------------+ +-------------+ +-------------+
§3. The three CLIs are to be found in the webs called inbuild, inform7
and inter (and these are the webs which tangle to the three complete tools).
Each module is also a web, and the above chart shows where it is: a module
in the INBUILD column, say syntax-module, is at the path inbuild/syntax-module,
for example. But as the diagram shows, it's shared code and runs in both
inbuild and inform7.
All three tools also contain the foundation module, a library of utility
code which is present in every Inform tool.