Of the functions listed in this section, only print_char, print_string,write_char, write_string, and write_check can be called in parallel.
print_char(v) {char 
bool}
Prints a character to standard output.
print_string(v) {[char] 
bool}
Prints a character string to standard output.
write_object_to_file(object, filename) {(a, [char]) 
bool :: (a in any)}
Writes an object to a file. The first argument is the object and the
second argument is a filename. For example
write_object_to_file([2,3,1,0],"/tmp/foo")
would write a vector of integers to the file /tmp/foo.
The data is stored in an internal format and can only be read back
using read_object_from_file.
write_string_to_file(a, filename) {([char], [char]) 
bool}
Writes a character string to the file named filename.
append_string_to_file(a, filename) {([char], [char]) 
bool}
Appends a character string to the file named filename.
read_object_from_file(object_type, filename) {(a, [char]) 
a :: (a in any)}
Reads an object from a file. The first argument is an object of the
same type as the object to be read, and the second argument is a
filename. For example, the call
read_object_from_file(0,"/tmp/foo")
would read an integer from the file /tmp/foo, and
read_object_from_file([] int,"/tmp/bar")
would read a vector of integers from the file /tmp/foo. The
object needs to have been stored using the function
write_object_to_file.
read_string_from_file(filename) {[char] 
[char]}
Reads a whole file into a character string.
read_int_seq_from_file(filename) {[char] 
[int]}
Reads a sequence of integers from the file named filename.
The file must start with a left parenthesis, contain the integers
separated by either white spaces, newlines or tabs, and end with
a right parenthesis. For example:
( 22 33 11 10 14 12 11 )represents the sequence [22, 33, 11, 10, 14, 12, 11].
read_float_seq_from_file(filename) {[char] 
[float]}
Reads a sequence of floats from the file named filename. The
file must start with a left parenthesis, contain the floats separated
by either white spaces, newlines or tabs, and end with a right
parenthesis. The file may contain integers (no .); these will be
coerced to floats.
open_in_file(filename) {[char] 
(stream, bool, [char])}
Opens a file for reading and returns a stream for that file
along with an error flag and an error message.
open_out_file(filename) {[char] 
(stream, bool, [char])}
Opens a file for writing and returns a stream for that file
along with an error flag and an error message. File pointers cannot
be returned to top-level. They must be used within a single top-level
call.
close_file(str) {stream 
(bool, [char])}
Closes a file given a stream. It returns an error flag and
an error message.
write_char(a, stream) {(char, stream) 
(bool, [char])}
Prints a character to the stream specified by stream.
It returns an error flag and error message.
write_string(a, stream) {([char], stream) 
(bool, [char])}
Prints a character string to the stream specified by stream.
It returns an error flag and error message.
read_char(stream) {stream 
(char, bool, [char])}
Reads a character from stream. If the end-of-file is reached,
the null character is returned along with the success flag set
to false.
read_string(delim, maxlen, stream)
{([char], int, stream) 
(([char], int), bool, [char])}
Reads a string from the stream stream. It will read until
one of the following is true (whichever comes first):
read_line(stream) {stream 
(([char], bool), bool, [char])}
Reads all the characters in stream up to a newline or the
end-of-file (whichever comes first). The newline is consumed and not
returned. As well as returning the line, it returns a boolean flag
indicating whether reading was terminated on a newline (f) or EOF
(t).
read_word(stream) {stream 
(([char], char, bool), bool, [char])}
Reads all the characters in stream up to a newline, space,
tab or the end-of-file (whichever comes first). The newline, space or
tab is consumed and not returned.
As well as returning the line, it returns a (char,bool) pair that indicates
on what character the word was terminated and whether it was terminated
on a EOF (the bool is t).
open_check(str, flag, err_message) {(a, bool, [char]) 
a :: (a in any)}
Checks if an open on a file succeeded and prints an error message if
it did not. For example, in the form
open_check(open_in_file("/usr/foo/bar")), if the open is successful
it will return a stream, otherwise it will print an error message and
return the null stream.
write_check(flag, err_message) {(bool, [char]) 
bool}
Checks if a write succeeded and prints an error message if it did
not. For example, in the form
write_check(write_string("foo",stream)), if the write is successful
it will return t, otherwise it will print an error message and
return f.
read_check(val, flag, err_message) {(a, bool, [char]) 
a :: (a in any)}
Checks if a read succeeded and prints an error message if it did not.
It also strips off the error information from the read functions. For
example, in the form read_check(read_char(stream)), if the read
is successful it will return the character which is read, otherwise it
will print an error message.
close_check(flag, err_message) {(bool, [char]) 
bool}
Checks if a close on a stream succeeded and prints an error message
if it did not. For example, in the form
close_check(close_file(stream)), if the close is successful it will
return t, otherwise it will print an error message and return
f.
nullstr {stream}
The null stream.
stdin {stream}
The standard input stream.
stdout {stream}
The standard output stream.
stderr {stream}
The standard error stream.