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56 lines
2.2 KiB
OpenEdge ABL
56 lines
2.2 KiB
OpenEdge ABL
[PackageTypes::] Package Types.
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To manage the different types of packages emitted by Inform.
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@h Package types.
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Inter code is a nested hierarchy of "packages", which can be assigned "types".
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Inter requires two types to exist, |_plain| and |_code|, and leaves the rest
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to the user (i.e., us) to define as we see fit. In fact Inform generates
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packages of slightly over 50 different types.
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At run time, package types are pointers to the inter symbol which defined them,
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but this is not a convenient way to refer to them in the Inform source code.
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Instead we use the following function:
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=
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inter_symbol *PackageTypes::get(inter_tree *I, text_stream *name) {
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inter_symbols_table *scope = InterTree::global_scope(I);
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inter_symbol *ptype = InterSymbolsTables::symbol_from_name(scope, name);
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if (ptype == NULL) {
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int enclose = TRUE;
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@<Decide if this package type is to be enclosing@>;
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ptype = Produce::new_symbol(scope, name);
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Produce::guard(Inter::PackageType::new_packagetype(
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Site::package_types(I), ptype,
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0, NULL));
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if (enclose) Produce::annotate_symbol_i(ptype, ENCLOSING_IANN, 1);
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}
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return ptype;
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}
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@ Most package types are "enclosing". Suppose that Inform is compiling
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something to go into the package, but finds that it needs to compile something
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else in order to do so -- for example, it's compiling code to set a variable
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to be equal to a literal piece of text, which must itself be compiled as a
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small array. Where does Inform put that array? If the current package is
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"enclosing", then Inform puts it into the package itself; and if not, then
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into the package holding the current package, if that in turn is "enclosing";
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and so on.
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It seems tidy to make all packages enclosing, and in fact (after much
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experiment) Inform nearly does that. But |_code| packages have to be an
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exception, because the Inter specification doesn't allow constants (and
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therefore arrays) to be defined inside |_code| packages.
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@<Decide if this package type is to be enclosing@> =
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if (Str::eq(name, I"_code")) enclose = FALSE;
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@ Symbol lookups by name are fast, but not instant, so we might some day
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want to optimise this by cacheing the result:
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=
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inter_symbol *PackageTypes::function(inter_tree *I) {
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return PackageTypes::get(I, I"_function");
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}
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