struct token_config config;
char *file_name;
int parse_error;
+ struct exec *prog;
## parse context
};
},
};
int doprint=0, dotrace=0, doexec=1, brackets=0;
- struct exec **prog;
int opt;
while ((opt = getopt_long(argc, argv, options, long_options, NULL))
!= -1) {
break;
}
if (ss)
- prog = parse_oceani(ss->code, &context.config,
- dotrace ? stderr : NULL);
+ parse_oceani(ss->code, &context.config,
+ dotrace ? stderr : NULL);
else {
fprintf(stderr, "oceani: cannot find section %s\n",
section);
exit(1);
}
} else
- prog = parse_oceani(s->code, &context.config,
- dotrace ? stderr : NULL);
- if (!prog) {
- fprintf(stderr, "oceani: fatal parser error.\n");
+ parse_oceani(s->code, &context.config,
+ dotrace ? stderr : NULL);
+ if (!context.prog) {
+ fprintf(stderr, "oceani: no program found.\n");
context.parse_error = 1;
}
- if (prog && doprint)
- print_exec(*prog, 0, brackets);
- if (prog && doexec && !context.parse_error) {
- if (!analyse_prog(*prog, &context)) {
+ if (context.prog && doprint)
+ print_exec(context.prog, 0, brackets);
+ if (context.prog && doexec && !context.parse_error) {
+ if (!analyse_prog(context.prog, &context)) {
fprintf(stderr, "oceani: type error in program - not running.\n");
exit(1);
}
- interp_prog(*prog, argv+optind+1);
+ interp_prog(context.prog, argv+optind+1);
}
- if (prog) {
- free_exec(*prog);
- free(prog);
+ if (context.prog) {
+ free_exec(context.prog);
}
while (s) {
struct section *t = s->next;
v = t->previous;
free_value(t->val);
+ if (t->min_depth == 0)
+ free_exec(t->where_decl);
free(t);
}
}
break;
}
+### Top level structure
+
+All the language elements so far can be used in various places. Now
+it is time to clarify what those places are.
+
+At the top level of a file there will be a number of declarations.
+Many of the things that can be declared haven't been described yet,
+such as functions, procedures, imports, named types, and probably
+more.
+For now there are two sorts of things that can appear at the top
+level. They are predefined constants and the main program. While the
+syntax will allow the main program to appear multiple times, that will
+trigger an error if it is actually attempted.
+
+The various declarations do not return anything. They store the
+various declarations in the parse context.
+
+###### Parser: grammar
+
+ $void
+ Ocean -> DeclarationList
+
+ DeclarationList -> Declaration
+ | DeclarationList Declaration
+
+ Declaration -> DeclareConstant
+ | DeclareProgram
+ | NEWLINE
+
+ ## top level grammar
+
+### The `const` section
+
+As well as being defined in with the code that uses them, constants
+can be declared at the top level. These have full-file scope, so they
+are always `InScope`. The value of a top level constant can be given
+as an expression, and this is evaluated immediately rather than in the
+later interpretation stage. Once we add functions to the language, we
+will need rules concern which, if any, can be used to define a top
+level constant.
+
+Constants are defined in a sectiont that starts with the reserved word
+`const` and then has a block with a list of assignment statements.
+For syntactic consistency, these must use the double-colon syntax to
+make it clear that they are constants. Type can also be given: if
+not, the type will be determined during analysis, as with other
+constants.
+
+###### top level grammar
+
+ DeclareConstant -> const Open ConstList Close
+ | const Open Newlines ConstList Close
+ | const Open SimpleConstList }
+ | const Open Newlines SimpleConstList }
+ | const : ConstList
+ | const SimpleConstList
+
+ ConstList -> ComplexConsts
+ ComplexConsts -> ComplexConst ComplexConsts
+ | ComplexConst
+ ComplexConst -> SimpleConstList NEWLINE
+ SimpleConstList -> Const ; SimpleConstList
+ | Const
+ | Const ; SimpleConstList ;
+
+ $*type
+ CType -> Type ${ $0 = $<1; }$
+ | ${ $0 = NULL; }$
+ $void
+ Const -> IDENTIFIER :: CType = Expression ${ {
+ int ok;
+ struct variable *v;
+
+ v = var_decl(config2context(config), $1.txt);
+ if (v) {
+ struct var *var = new_pos(var, $1);
+ v->where_decl = var;
+ v->where_set = var;
+ var->var = v;
+ v->constant = 1;
+ } else {
+ v = var_ref(config2context(config), $1.txt);
+ tok_err(config2context(config), "error: name already declared", &$1);
+ type_err(config2context(config), "info: this is where '%v' was first declared",
+ v->where_decl, NULL, 0, NULL);
+ }
+ do {
+ ok = 1;
+ propagate_types($5, config2context(config), &ok, $3, 0);
+ } while (ok == 2);
+ if (!ok)
+ config2context(config)->parse_error = 1;
+ else if (v) {
+ v->val = interp_exec($5);
+ }
+ } }$
+
+
### Finally the whole program.
Somewhat reminiscent of Pascal a (current) Ocean program starts with
the keyword "program" and a list of variable names which are assigned
values from command line arguments. Following this is a `block` which
-is the code to execute.
+is the code to execute. Unlike Pascal, constants and other
+declarations come *before* the program.
As this is the top level, several things are handled a bit
differently.
###### Binode types
Program,
-###### Parser: grammar
+###### top level grammar
+
+ DeclareProgram -> Program ${ {
+ struct parse_context *c = config2context(config);
+ if (c->prog)
+ type_err(c, "Program defined a second time",
+ $1, NULL, 0, NULL);
+ else
+ c->prog = $<1;
+ } }$
+
$*binode
Program -> program OpenScope Varlist Block OptNL ${
###### test: hello
+ const:
+ pi ::= 3.1415926
+ four ::= 2 + 2 ; five ::= 10/2
+ const pie ::= "I like Pie";
+ cake ::= "The cake is"
+ ++ " a lie"
+
program A B:
print "Hello World, what lovely oceans you have!"
+ print "are there", five, "?"
+ print pi, pie, "but", cake
+
/* When a variable is defined in both branches of an 'if',
* and used afterwards, the variables are merged.
*/
code / ocean / blobdiff