132 lines
2.9 KiB
Text
132 lines
2.9 KiB
Text
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# 1 "scope.cppo"
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(* This example shows that the definition of FOO that is nested inside
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the (multi-line) definition of BAR affects only the body of the
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definition of BAR. It does not affect the text that follows a call
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to BAR. So, a multi-line macro definition acts as a scope delimiter. *)
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# 11 "scope.cppo"
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"definition of FOO at the top level"
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# 11 "scope.cppo"
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(* expands to "definition of FOO at the top level" *)
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# 12 "scope.cppo"
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"definition of FOO inside BAR" (* expands to "definition of FOO inside BAR" *)
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# 13 "scope.cppo"
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"definition of FOO at the top level"
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# 13 "scope.cppo"
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(* expands to "definition of FOO at the top level" *)
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(* If one wishes to delimit a scope, without actually defining a macro,
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one can use #scope ... #endscope. *)
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# 20 "scope.cppo"
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"first definition of HELLO"
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# 20 "scope.cppo"
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(* expands to "first definition of HELLO" *)
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# 24 "scope.cppo"
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"second definition of HELLO"
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# 24 "scope.cppo"
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(* expands to "second definition of HELLO" *)
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HELLO (* this does not expand *)
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(* The effect of #scope ... #endscope can be simulated by writing
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#def DUMMY ... #enddef DUMMY #undef DUMMY
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but this is a bit unnatural. *)
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# 36 "scope.cppo"
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"definition of HELLO inside the scope" (* expands to "definition of HELLO inside the scope" *)
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# 38 "scope.cppo"
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HELLO (* this does not expand *)
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(* Another simple example. *)
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# 44 "scope.cppo"
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let x =
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# 44 "scope.cppo"
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"I am defined"
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# 44 "scope.cppo"
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(* expands to "I am defined" *)
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# 47 "scope.cppo"
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let y =
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# 47 "scope.cppo"
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42
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# 47 "scope.cppo"
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(* expands to 42 *)
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(* Check that the effect of #undef is also local.
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This example relies on the above definition of HI. *)
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# 54 "scope.cppo"
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let qwd = HI (* HI is not recognized as a macro and expands to itself *)
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let z =
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# 56 "scope.cppo"
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42
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# 56 "scope.cppo"
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(* expands to 42 *)
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(* Scopes can be nested. *)
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# 61 "scope.cppo"
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let x =
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# 61 "scope.cppo"
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0
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# 61 "scope.cppo"
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(* expands to 0 *)
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# 65 "scope.cppo"
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let y =
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# 65 "scope.cppo"
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1
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# 65 "scope.cppo"
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(* expands to 1 *)
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# 69 "scope.cppo"
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let z =
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# 69 "scope.cppo"
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2
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# 69 "scope.cppo"
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(* expands to 2 *)
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let _ =
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# 71 "scope.cppo"
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1
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# 71 "scope.cppo"
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(* expands to 1 *)
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let _ =
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# 73 "scope.cppo"
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0
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# 73 "scope.cppo"
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(* expands to 0 *)
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(* Another example of nesting. *)
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# 81 "scope.cppo"
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let message1 =
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# 81 "scope.cppo"
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"Hello, "
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# 81 "scope.cppo"
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^
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# 81 "scope.cppo"
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"man"
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# 83 "scope.cppo"
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(* Here, MAN is no longer defined, but HELLO still is. *)
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let message2 =
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# 84 "scope.cppo"
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"Hello, "
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# 84 "scope.cppo"
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^ "world"
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