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Diffstat (limited to 'POSIX')
| -rw-r--r-- | POSIX | 95 |
1 files changed, 95 insertions, 0 deletions
@@ -0,0 +1,95 @@ +Right now, the numeric vs. string comparisons are screwed up in draft +11.2. What prompted me to check it out was the note in gnu.bug.utils +which observed that gawk was doing the comparison $1 == "000" +numerically. I think that we can agree that intuitively, this should +be done as a string comparison. Version 2.13.2 of gawk follows the +current POSIX draft. Following is how I (now) think this +stuff should be done. + +1. A numeric literal or the result of a numeric operation has the NUMERIC + attribute. + +2. A string literal or the result of a string operation has the STRING + attribute. + +3. Fields, getline input, FILENAME, ARGV elements, ENVIRON elements and the + elements of an array created by split() that are numeric strings + have the STRNUM attribute. Otherwise, they have the STRING attribute. + Uninitialized variables also have the STRNUM attribute. + +4. Attributes propagate across assignments, but are not changed by + any use. (Although a use may cause the entity to acquire an additional + value such that it has both a numeric and string value -- this leaves the + attribute unchanged.) + +When two operands are compared, either string comparison or numeric comparison +may be used, depending on the attributes of the operands, according to the +following (symmetric) matrix: + + +---------------------------------------------- + | STRING NUMERIC STRNUM +--------+---------------------------------------------- + | +STRING | string string string + | +NUMERIC | string numeric numeric + | +STRNUM | string numeric numeric +--------+---------------------------------------------- + +So, the following program should print all OKs. + +echo '0e2 0a 0 0b +0e2 0a 0 0b' | +$AWK ' +NR == 1 { + num = 0 + str = "0e2" + + print ++test ": " ( (str == "0e2") ? "OK" : "OOPS" ) + print ++test ": " ( ("0e2" != 0) ? "OK" : "OOPS" ) + print ++test ": " ( ("0" != $2) ? "OK" : "OOPS" ) + print ++test ": " ( ("0e2" == $1) ? "OK" : "OOPS" ) + + print ++test ": " ( (0 == "0") ? "OK" : "OOPS" ) + print ++test ": " ( (0 == num) ? "OK" : "OOPS" ) + print ++test ": " ( (0 != $2) ? "OK" : "OOPS" ) + print ++test ": " ( (0 == $1) ? "OK" : "OOPS" ) + + print ++test ": " ( ($1 != "0") ? "OK" : "OOPS" ) + print ++test ": " ( ($1 == num) ? "OK" : "OOPS" ) + print ++test ": " ( ($2 != 0) ? "OK" : "OOPS" ) + print ++test ": " ( ($2 != $1) ? "OK" : "OOPS" ) + print ++test ": " ( ($3 == 0) ? "OK" : "OOPS" ) + print ++test ": " ( ($3 == $1) ? "OK" : "OOPS" ) + print ++test ": " ( ($2 != $4) ? "OK" : "OOPS" ) # 15 +} +{ + a = "+2" + b = 2 + if (NR % 2) + c = a + b + print ++test ": " ( (a != b) ? "OK" : "OOPS" ) # 16 and 22 + + d = "2a" + b = 2 + if (NR % 2) + c = d + b + print ++test ": " ( (d != b) ? "OK" : "OOPS" ) + + print ++test ": " ( (d + 0 == b) ? "OK" : "OOPS" ) + + e = "2" + print ++test ": " ( (e == b "") ? "OK" : "OOPS" ) + + a = "2.13" + print ++test ": " ( (a == 2.13) ? "OK" : "OOPS" ) + + a = "2.130000" + print ++test ": " ( (a != 2.13) ? "OK" : "OOPS" ) + + if (NR == 2) { + CONVFMT = "%.6f" + print ++test ": " ( (a == 2.13) ? "OK" : "OOPS" ) + } +}' |