Implemented as follows:
Usage: expr EXPRESSION
or: expr OPTION
--help display this help and exit
--version output version information and exit
Print the value of EXPRESSION to standard output. A blank line below
separates increasing precedence groups. EXPRESSION may be:
ARG1 | ARG2 ARG1 if it is neither null nor 0, otherwise ARG2
ARG1 & ARG2 ARG1 if neither argument is null or 0, otherwise 0
ARG1 < ARG2 ARG1 is less than ARG2
ARG1 <= ARG2 ARG1 is less than or equal to ARG2
ARG1 = ARG2 ARG1 is equal to ARG2
ARG1 != ARG2 ARG1 is unequal to ARG2
ARG1 >= ARG2 ARG1 is greater than or equal to ARG2
ARG1 > ARG2 ARG1 is greater than ARG2
ARG1 + ARG2 arithmetic sum of ARG1 and ARG2
ARG1 - ARG2 arithmetic difference of ARG1 and ARG2
ARG1 * ARG2 arithmetic product of ARG1 and ARG2
ARG1 / ARG2 arithmetic quotient of ARG1 divided by ARG2
ARG1 % ARG2 arithmetic remainder of ARG1 divided by ARG2
STRING : REGEXP [NOT IMPLEMENTED] anchored pattern match of REGEXP in STRING
match STRING REGEXP [NOT IMPLEMENTED] same as STRING : REGEXP
substr STRING POS LENGTH [NOT IMPLEMENTED] substring of STRING, POS counted from 1
index STRING CHARS [NOT IMPLEMENTED] index in STRING where any CHARS is found, or 0
length STRING [NOT IMPLEMENTED] length of STRING
+ TOKEN interpret TOKEN as a string, even if it is a
keyword like 'match' or an operator like '/'
( EXPRESSION ) value of EXPRESSION
Beware that many operators need to be escaped or quoted for shells.
Comparisons are arithmetic if both ARGs are numbers, else lexicographical.
Pattern matches return the string matched between \( and \) or null; if
\( and \) are not used, they return the number of characters matched or 0.
Exit status is 0 if EXPRESSION is neither null nor 0, 1 if EXPRESSION is null
or 0, 2 if EXPRESSION is syntactically invalid, and 3 if an error occurred.
Environment variables:
* EXPR_DEBUG_TOKENS=1 dump expression's tokens
* EXPR_DEBUG_RPN=1 dump expression represented in reverse polish notation
* EXPR_DEBUG_SYA_STEP=1 dump each parser step
* EXPR_DEBUG_AST=1 dump expression represented abstract syntax tree
Improve handling of unicode on Windows
Disable a few crates on Windows that abuse unix APIs too much
Signed-off-by: Peter Atashian <retep998@gmail.com>
I removed unused linker flags, added platform-specific linker flags, and
used DYLD_LIBRARY_PATH (instead of DYLD_INSERT_LIBRARIES) for loading
the dynamic library. I also removed an unused variable mutation.
There are several areas needing improvement:
1) add tests for hard links
2) add implementation for uncommon flags (-d, -L, -n, -P, -r)
3) align error messages more closely with GNU implementation
I switched over to the getopts crate on crates.io, instead of Rust's
private implementation. This will allow coreutils to build for Rust 1.0.
I'm splitting the updates into several commits for better reviewing.
This commit adds `cargo update` to the distclean target in the
makefile. This updates the Cargo.lock file when clearing the
deps directory.
In addition, it adds a faster implementation of the Sieve of
Eratosthenes for use by `src/factor/gen_table.rs` and `test/factor.rs`.
I created random data to test several cases. I verified that the data is
split into the correct number of files and can also be reassembled into
the original file.
This change does the following:
1. Updates the arithmetic functions in `src/factor/numeric.rs` to
correctly handle all cases up to 2^64. When numbers are larger
than 2^63, we fall back to slightly slower routines that check
for and handle overflow.
2. Since the arithmetic functions will now not overflow, we no longer
need the safety net trial division implementation. We now always
use Pollard's rho after eliminating small (<=13 bit) primes.
3. Slight tweak in `src/factor/gen_table.rs` to generate the first
1027 primes, which means we test every prime of 13 or fewer bits
before going into Pollard's rho. Includes corresponding update in
`src/factor/prime_table.rs` and the Makefile to reflect this.
4. Add a new test that generates random numbers with exclusively
large (14 to 50 bit) prime factors. This exercises the possible
overflow paths.
5. Add another new test that checks the `is_prime()` function against
a few dozen 64-bit primes. Again this is to exercise possible
overflow paths.
Add a test for `factor`.
This commit also pulls factor's Sieve implementation into its own module
so that the factor test can use it.
Finally, slight refactoring for clarity in gen_table.rs.
This commit builds upon @wikol's Pollard rho implementation.
It adds the following:
1. A generator for prime inverse tables. With these, we can do
very fast divisibility tests (a single multiply and comparison)
for small primes (presently, the first 1000 primes are in the
table, which means all numbers of ~26 bits or less can be
factored very quickly.
2. Always try prime inverse tables before jumping into Pollard's
rho method or using trial division.
3. Since we have eliminated all small factors by the time we're
done with the table division, only use slow trial division when
the number is big enough to cause overflow issues in Pollard's
rho, and jump out of trial division and into Pollard's rho as
soon as the number is small enough.
4. Updates the Makefile to regenerate the prime table if it's not
up-to-date.
This rule will test each program, ignore all output, and return pass or
fail depending on whether the test has errors. This is the equivalent of
"make build-check", but for tests.
