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@@ -0,0 +1,48 @@
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+*In place* variables are introduced to relieve VAR section from variables which have very local scope or temporary nature. *In place* variable is declared and initialized in the same place where it is needed so there is no gap between its declaration and usage.
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+
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+### Syntax
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+*In place* variable can be declared wherever the grammar *statement* is suitable:
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+
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+ InPlaceStatement = ident "<-" expression
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+
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+Example:
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+
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+ i <- 123;
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+
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+*In place* variable is declared and assigned in the same time. The type of variable is not specified but deduced from the expression on the right. In the example above
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+variable will have type INTEGER. In the following example the variable will have the same type as a result of PROCEDURE f:
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+
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+ x <- f();
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+
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+Although the type is not specified explicitly a variable is still statically typed (its type cannot be changed) with deduced type in the same way as a regular variable (declared in VAR section).
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+
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+*In place* variable behaves in the same way as a regular variable (declared in VAR section). It can be reassigned or passed as a VAR parameter to procedure. When variable is initialized with a record type - it will be copied as if variable of this record type was declared in VAR section and then assigned to another variable of record type.
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+
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+ PROCEDURE p(a1: SomeRecord; VAR a2: SomeRecord);
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+ BEGIN
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+ v1 <- a1; (* a1 will be copied to v1 *)
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+ v2 <- a2; (* a2 will be copied to v2 *)
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+ END p;
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+
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+Please notice that *v1* and *v2* will be copies (modifiable) of variables of type SomeRecord even if some descendants of type SomeRecord were passed to the procedure *p* as actual parameters.
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+
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+### Scope rules
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+
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+*In place* variable is visible from the place of declaration textually down to the end of procedure or outer IF/WHILE/FOR's END or ELSE/ELSIF/CASE branch.
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+
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+*In place* variable name cannot duplicate any other variable name from outer scopes up to procedure scope.
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+
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+ PROCEDURE p();
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+ VAR v1: INTEGER;
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+ BEGIN
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+ v1 <- 1; (* compile error: 'v1' already declared in procedure scope *)
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+ v2 <- 2; (* OK *)
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+ IF expression THEN
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+ v2 <- 2; (* compile error: 'v2' already declared in procedure scope *)
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+ v3 <- 3; (* OK *)
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+ ELSE
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+ v3 <- 3; (* OK, another v3 is declared in separate scope *)
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+ END;
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+
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+ v3 := 3; (* compile error: undeclared identifier: 'v3')
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+ END p;
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Vladislav Folts