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| author | Denys Vlasenko | 2023-06-13 18:27:19 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2023-06-14 00:41:18 +0200 |
| commit | 8acbf31708779e7ad559775c9db4ebd7a962be33 (patch) | |
| tree | 6ebbb1943faa703f53257b6b64c3426e9cf647d6 /shell/ash_test | |
| parent | 373f64eef3cc121d7531522ef654feb0a8068d5a (diff) | |
| download | busybox-8acbf31708779e7ad559775c9db4ebd7a962be33.zip busybox-8acbf31708779e7ad559775c9db4ebd7a962be33.tar.gz | |
shell/math: document ternary ?: op's weirdness, add code comments
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'shell/ash_test')
| -rw-r--r-- | shell/ash_test/ash-arith/arith-precedence1.right | 3 | ||||
| -rwxr-xr-x | shell/ash_test/ash-arith/arith-precedence1.tests | 13 |
2 files changed, 16 insertions, 0 deletions
diff --git a/shell/ash_test/ash-arith/arith-precedence1.right b/shell/ash_test/ash-arith/arith-precedence1.right index 7f407b5..3f9320a 100644 --- a/shell/ash_test/ash-arith/arith-precedence1.right +++ b/shell/ash_test/ash-arith/arith-precedence1.right @@ -1 +1,4 @@ 4:4 +4:4 +4:4 +4:4 diff --git a/shell/ash_test/ash-arith/arith-precedence1.tests b/shell/ash_test/ash-arith/arith-precedence1.tests index 964ae4e..bfef052 100755 --- a/shell/ash_test/ash-arith/arith-precedence1.tests +++ b/shell/ash_test/ash-arith/arith-precedence1.tests @@ -1,2 +1,15 @@ exec 2>&1 +# bash documentation says that precedence order is: +# ... +# expr ? expr1 : expr2 +# = *= /= %= += -= <<= >>= &= ^= |= +# exprA , exprB +# but in practice, the rules for expr1 and expr2 are different: +# assignments and commas in expr1 have higher precedence than :?, +# but in expr2 they haven't: +# "v ? 1,2 : 3,4" is parsed as "(v ? (1,2) : 3),4" +# "v ? a=2 : b=4" is parsed as "(v ? (a=1) : b)=4" (thus, this is a syntax error) +echo 4:$((0 ? 1,2 : 3,4)) +echo 4:$((1 ? 1,2 : 3,4)) echo 4:"$((0 ? 1,2 : 3,4))" +echo 4:"$((1 ? 1,2 : 3,4))" |