Read tables and read macros

Read tables package a number of parameters for use by programs which parse, generate, or otherwise manipulate external syntax of programs and objects. In particular, every read table contains a table which maps characters to objects which describe their lexical properties.

There is a standard read table which contains the standard read syntax for all characters. In order to define nonstandard read syntax, one must create a new read table using MAKE-READ-TABLE, and arrange for READ-OBJECT to use the new read table instead of the standard read table, e.g. by doing (SET (PORT-READ-TABLE ... ) ... ).

$\begin{inset}{} Creates a new read table which is a copy of {\it read-table\/}. ... ...AKE-READ-TABLE STANDARD-READ-TABLE '*MY-READ-TABLE*)) \end{tabbing}} \end{inset}$

$\begin{inset}{} The standard {\bf T} read table. \end{inset}$

$\begin{inset}{} The value of {\tt VANILLA-READ-TABLE} is a read table in which a... ...) \- \\ $\Longrightarrow$\ (FOO \char93 [Symbol ()]) \end{tabbing}} \end{inset}$

Settable

$\begin{inset}{} Access {\it character\/}'s read syntax in {\it table\/}. The ent... ...a read table are immutable, and so their entries may not be changed. \end{inset}$

$\begin{inset}{} Read macros should return this object, which is treated speciall... ...slash$}NEWLINE) NOTHING-READ) \\ (ELSE (LOOP))))))) \end{tabbing}} \end{inset}$

Operation

$\begin{inset}{} If an object which returns true to the {\tt DELIMITING-READ-MACR... ... \ldots\ ) \\ ((DELIMITING-READ-MACRO? SELF) T))) \end{tabbing}} \end{inset}$

$\begin{inset}{} The two procedures {\tt MAKE-LIST-READER} and {\tt LIST-TERMINAT... ...handle the {\tt DELIMITING-READ-MACRO?} operation by returning true. \end{inset}$

$\begin{inset}{} Given a list reader, returns its list terminator. See {\tt LIST-READER}, above. \end{inset}$