3.6.1 AutoGen Macro Syntax

The general syntax is:

[ { <native-macro-name> | <user-defined-name> } ] [ <arg> ... ]

The syntax for <arg> depends on the particular macro, but is generally a full expression (see expression syntax). Here are the exceptions to that general rule:

1. INVOKE macros, implicit or explicit, must be followed by a list of name/string value pairs. The string values are simple expressions, as described above.

   That is, the INVOKE syntax is one of these two:

   <user-macro-name> [ <name> [ = <expression> ] ... ]
   
   INVOKE <name-expression> [ <name> [ = <expression> ] ... ]
   

2. AutoGen FOR macros must be in one of three forms:

   FOR <name> [ <separator-string> ]
   
   FOR <name> (...Scheme expression list)
   
   FOR <name> IN <string-entry> [ ... ]
   

   where:

   ‘<name>’

   must be a simple name.

   ‘<separator-string>’

   is inserted between copies of the enclosed block. Do not try to use “IN” as your separator string. It won’t work.

   ‘<string-entry>’

   is an entry in a list of strings. “<name>” is assigned each value from the “IN” list before expanding the FOR block.

   ‘(...Scheme expression list)’

   is expected to contain one or more of the for-from, for-to, for-by, and for-sep functions. (See FOR, and AutoGen Functions)

   The first two forms iterate over the FOR block if <name> is found in the AutoGen values. The last form will create the AutoGen value named <name>.

3. AutoGen DEFINE macros must be followed by a simple name. Anything after that is ignored. Consequently, that “comment space” may be used to document any named values the macro expects to have set up as arguments. See DEFINE.
4. The AutoGen COMMENT, ELSE, ESAC and the END* macros take no arguments and ignore everything after the macro name (e.g. see COMMENT)