Marker trait for all built-in entities.
A built-in procedure with its parameter information.
A built-in type with an implicit definition that the compiler must have special knowledge about.
A user-defined constant entity represented by a constant declaration.
A built-in value of some type that is represented by a particular integer value.
A user-defined module represented by a module declaration.
Information about a particular parameter.
A parameter is a variable augmented with a passing mode.
A procedure entity represented by a procedure declaration.
An entity representing by a user-provided type declaration.
A user-defined type.
A variable entity including a reference to its types' definition.
Built-in Boolean type.
Built-in Boolean type.
Check an AST node for semantic errors.
Check an AST node for semantic errors. Report any errors using the messaging module. This default implementation just ask the node's children to check themselves.
Check for non-local variable and procedure accesses.
Check for non-local variable and procedure accesses. In the L3 language non-local variable accesses are disallowed, unless they are to a variable at the top level. Non-local procedure accesses are just disallowed.
The default environment.
The default environment.
The default environment with pre-defined procedures added.
The default environment with pre-defined procedures added.
The program entity referred to by an identifier definition or use.
The program entity referred to by an identifier definition or use. In the case of a definition it's the thing being defined, so define it to be a reference to the declaration. If it's already defined, return a entity that indicates a multiple definition. In the case of a use, it's the thing defined elsewhere that is being referred to here, so look it up in the environment.
The entity for an identifier definition as given by its declaration context.
The entity for an identifier definition as given by its declaration context.
The environment containing bindings for all identifiers visible at the given node.
The environment containing bindings for all identifiers visible at the given node. It starts at the module declaration with the default environment. At blocks we enter a nested scope which is removed on exit from the block. At constant and type declarations the left-hand side binding is not in scope on the right-hand side. Each identifier definition just adds its binding to the chain. The envout cases for assignment and expression mean that we don't need to traverse into those constructs, since declarations can't occur there.
Blocks that are immediately inside procedure decls do not introduce new scopes since the procedure itself does.
Blocks that are immediately inside procedure decls do not introduce new scopes since the procedure itself does. This computation overrides the one earlier that pushes a scope for all blocks. Don't include the procedure name in the scope of its own body.
Similarly for envin we don't need to leave a scope for a procedure block, since we didn't enter one.
Similarly for envin we don't need to leave a scope for a procedure block, since we didn't enter one. The IdnDef that is for a ProcDecl needs to be in the outer scope, but not in the scope of its own body. All arguments and local declarations go in the nested scope.
Is an expression expected to be constant or not? Either the expression is the root of an expected constant expression or its parent expression is expected to be constant.
Is an expression expected to be constant or not? Either the expression is the root of an expected constant expression or its parent expression is expected to be constant.
Built-in false constant.
Built-in false constant.
Built-in integer type.
Built-in integer type.
Return true if the given type is Boolean or an unknown type.
Return true if the given type is Boolean or an unknown type.
Return true if the entity is erroneous or is a constant.
Return true if the entity is erroneous or is a constant.
Return true if the entity is an error, false otherwise.
Return true if the entity is an error, false otherwise.
Return true if the given type is integer or an unknown type.
Return true if the given type is integer or an unknown type.
Return true if the expression can legally appear on the left-hand side of an assignment statement.
Return true if the expression can legally appear on the left-hand side of an assignment statement. At this level only allow identifiers of variables or things we don't know anything about. The true default is used so that this computation can be used in redefinitions.
Return true if the entity is erroneous or is a module.
Return true if the entity is erroneous or is a module.
Return true if the identifier is an r-value and hence its value can be used (ie.
Return true if the identifier is an r-value and hence its value can be used (ie. it's erroneous or is a constant, value or variable).
Return true if the entity is erroneous or is a type.
Return true if the entity is erroneous or is a type.
Parameters are variables too.
Parameters are variables too.
Is an expression constant or not? Unknown entities are constant.
Is an expression constant or not? Unknown entities are constant. Strictly speaking we only need to support integer expressions here, but we treat Boolean ones as constant in the same way so that we avoid spurious errors. Type analysis will reject Boolean constant expressions anyway.
Level of a node considering the module level to be zero and incrementing each time we enter a nested procedure declaration.
Level of a node considering the module level to be zero and incrementing each time we enter a nested procedure declaration.
The built-in Read procedure.
The built-in Read procedure.
Is this expression the root of what is expected to be a constant expression? At this level only expressions on the RHS of a constant declaration have this property.
Is this expression the root of what is expected to be a constant expression? At this level only expressions on the RHS of a constant declaration have this property.
Built-in true constant.
Built-in true constant.
A type that is unknown, eg because the typed thing is erroneously defined.
A type that is unknown, eg because the typed thing is erroneously defined.
What is the value of an integer expression? Only needs to be valid if the expression is an integer constant (see isconst above) and is defined (eg, no divide by zero.
What is the value of an integer expression? Only needs to be valid if the expression is an integer constant (see isconst above) and is defined (eg, no divide by zero.) Returns zero in all other cases. FIXME: Ignores issues of overflow.
The built-in Write procedure.
The built-in Write procedure.
The built-in WriteLn procedure.
The built-in WriteLn procedure.