read-command converts a command line into a list of strings
suitable for parsing by
getopt. The syntax of command lines
supported resembles that of popular shells.
updates port to point to the first character past the command
If an end of file is encountered in the input before any characters are found that can begin an object or comment, then an end of file object is returned.
The port argument may be omitted, in which case it defaults to the
value returned by
The fields into which the command line is split are delimited by
whitespace as defined by
char-whitespace?. The end of a command
is delimited by end-of-file or unescaped semicolon (;) or
newline. Any character can be literally included in a field by
escaping it with a backslach (\).
The initial character and types of fields recognized are:
The next character has is taken literally and not interpreted as a field delimiter. If \ is the last character before a newline, that newline is just ignored. Processing continues from the characters after the newline as though the backslash and newline were not there.
The characters up to the next unescaped " are taken literally, according to [R4RS] rules for literal strings (see Strings in Revised(4) Scheme).
One scheme expression is
read starting with this character. The
read expression is evaluated, converted to a string
display), and replaces the expression in the returned
Semicolon delimits a command. Using semicolons more than one command can appear on a line. Escaped semicolons and semicolons inside strings do not delimit commands.
The comment field differs from the previous fields in that it must be
the first character of a command or appear after whitespace in order to
be recognized. # can be part of fields if these conditions are
not met. For instance,
ab#c is just the field ab#c.
Introduces a comment. The comment continues to the end of the line on
which the semicolon appears. Comments are treated as whitespace by
read-dommand-line and backslashes before newlines in
comments are also ignored.
read-options-file converts an options file into a list of
strings suitable for parsing by
getopt. The syntax of options
files is the same as the syntax for command
lines, except that newlines do not terminate reading (only ;
or end of file).
If an end of file is encountered before any characters are found that can begin an object or comment, then an end of file object is returned.