Editing SAIL (programming language) (section)

===Compiler directives===
As a systems programming language, performance was important and to help with this, SAIL included a {{code|DEFINE}} which used string-replacement in a fashion similar to C's {{code|#define}} macros.{{sfn|Smith|1976|p=25}} A difference was that the delimiters around the substitution had to be defined, for instance {{code|REQUIRE "[][]" DELIMITERS;DEFINE maxSize{{=}}[100];}}. One common use of these macros was to define character constants like {{code|CRLF}}, as these were not part of the basic language.{{sfn|Smith|1976|p=25}} Another was to redefine the {{code|COMMENT}} statement to the shorter {{code|!}}.{{sfn|Smith|1976|p=26}}

The system also included a [[conditional compilation]] system using statements, as opposed to pre-processor directives as found in C. {{code|IFCR}} would compile the blocks between the corresponding {{code|THENC}} and {{code|ELSEC}} or {{code|ENDC}}. The condition in the IFCR must be known at compile time, so, like C, was normally a {{code|DEFINE}}d value.{{sfn|Smith|1976|p=44}}