Previous Next

                                         50
CHAPTER 3                                                                       Syntax




                         TABLE 3.1 White-space characters
DECIMAL         HEXADECIMAL            OCTAL             NAME

0               00                     000               Null (NUL)

9               09                     011               Tab (HT)

10              0A                     012               Line feed (LF)

12              0C                     014               Form feed (FF)

13              0D                     015               Carriage return (CR)

32              20                     040               Space (SP)

The carriage return (CR) and line feed (LF) characters, also called newline
characters, are treated as end-of-line (EOL) markers. The combination of a
carriage return followed immediately by a line feed is treated as one EOL marker.
For the most part, EOL markers are treated the same as any other white-space
characters. However, sometimes an EOL marker is required or recommended—
that is, the following token must appear at the beginning of a line.

Note: The examples in this book illustrate a recommended convention for arranging
tokens into lines. However, the examples’ use of white space for indentation is purely
for clarity of exposition and is not recommended for practical use.

The delimiter characters (, ), <, >, [, ], {, }, /, and % are special. They delimit
syntactic entities such as strings, arrays, names, and comments. Any of these
characters terminates the entity preceding it and is not included in the entity.

All characters except the white-space characters and delimiters are referred to as
regular characters. These characters include 8-bit binary characters that are
outside the ASCII character set. A sequence of consecutive regular characters
comprises a single token.

Note: PDF is case-sensitive; corresponding uppercase and lowercase letters are con-
sidered distinct.

Previous Next