An overview of the final module's role and abilities.
§1. Prerequisites. The final module is a part of the Inform compiler toolset. It is presented as a literate program or "web". Before diving in:
- (a) It helps to have some experience of reading webs: see inweb for more.
- (b) The module is written in C, in fact ANSI C99, but this is disguised by the fact that it uses some extension syntaxes provided by the inweb literate programming tool, making it a dialect of C called InC. See inweb for full details, but essentially: it's C without predeclarations or header files, and where functions have names like Tags::add_by_name rather than just add_by_name.
- (c) This module uses other modules drawn from the compiler (see structure), and also uses a module of utility functions called foundation. For more, see A Brief Guide to Foundation (in foundation).
§2. Finally final. The final module is aptly named, in that it is the very last stage in compiling an Inform project. Everything up to this module has been generating a tree of Inter code, which is (to a large extent) an abstract, general-purpose description of a program. We finally turn that into an Inform 6 program, or a C program, or some other concrete expression of that program.
This module has a very simple interface to the rest of the tool chain: it simply provides a single Inter pipeline stage called generate. See CodeGen::create_pipeline_stage. When this stage is reached, the function CodeGen::run_pipeline_stage is run. This then creates a code_generation object, which holds all the temporary storage and configuration details for a single act of code-generation. The most important of those details is the choice of which code_generator to use — see below.
§3. The module creates a small number of //code_generator//s, one for each possible output format. For example, I6Target::create_generator creates one which represents "output Inform 6 code, please"; CTarget::create_generator creates one for "output ANSI C-99 code, please".
§4. It seems likely that many if not most of the formats we will ever need to generate will be procedural programming languages of the sort usually called C-like, and we want to avoid duplicated effort. A generic algorithm called Vanilla is therefore provided: a generator can, if it wishes, make use of this to simplify its work, and both our C and Inform 6 generators do so.