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@@ -16249,7 +16249,7 @@ not (False if input_int() == 1 else 0)
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Languages that allow expressions to produce different kinds of values
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are called \emph{polymorphic}, a word composed of the Greek roots
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-``poly'', meaning ``many'', and ``morph'', meaning ``shape''. There
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+``poly'', meaning ``many'', and ``morphos'', meaning ``form''. There
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are several kinds of polymorphism in programming languages, such as
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subtype polymorphism and parametric
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polymorphism~\citep{Cardelli:1985kx}. The kind of polymorphism we
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@@ -16265,8 +16265,8 @@ given anything else it returns \FALSE{}.
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Furthermore, even when primitive operations restrict their inputs to
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values of a certain type, this restriction is enforced at runtime
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-instead of during compilation. For example, the following tuple read
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-operation results in a run-time error because it requires a tuple, not
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+instead of during compilation. For example, the following expression
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+results in a run-time error because referencing a component requires a tuple, not
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a Boolean such as \TRUE{}.
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%
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{\if\edition\racketEd
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@@ -16400,8 +16400,8 @@ The concrete and abstract syntax of \LangDyn{}, our subset of
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\racket{Racket}\python{Python}, is defined in
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Figures~\ref{fig:r7-concrete-syntax} and \ref{fig:r7-syntax}.
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%
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-There is no type checker for \LangDyn{} because it is not a statically
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-typed language (it's dynamically typed!).
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+There is no type checker for \LangDyn{} because dynamically typed
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+languages check types at runtime.
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The definitional interpreter for \LangDyn{} is presented in
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\racket{Figure~\ref{fig:interp-Ldyn}}
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@@ -16460,14 +16460,14 @@ If they are not, a \code{trapped-error} is raised. Recall from
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Section~\ref{sec:interp_Lint} that when a definition interpreter
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raises a \code{trapped-error} error, the compiled code must also
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signal an error by exiting with return code \code{255}. A
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-\code{trapped-error} is also raised if the index is not less than
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+\code{trapped-error} is also raised if the index is not less than the
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length of the vector.
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}
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%
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\python{If they are not, an exception is raised. The compiled code
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must also signal an error by exiting with return code \code{255}. A
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- exception is also raised if the index is not less than length of the
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- tuple.}
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+ exception is also raised if the index is not less than the length of the
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+ tuple or if it is negative.}
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\begin{figure}[tbp]
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{\if\edition\racketEd
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Peter Thiemann