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commonstrcmd: Reduce scope of error case

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This commit is contained in:
Andreas Nordal 2019-08-03 14:54:27 +02:00
parent 88631be68d
commit 7bc9a9cd73
1 changed files with 26 additions and 21 deletions
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47
src/commonstrcmd.rs
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@ -115,27 +115,10 @@ pub fn common_str_cmd(
tri: Transition::Push(ext),
pre: i, len: 0, alt: None
});
} else if predlen(&is_decimal, &horizon[i+1 ..]) > 1 {
return CommonStrCmdResult::Err(UnsupportedSyntax {
typ: "Unsupported syntax: Syntactic pitfall",
ctx: horizon.to_owned(),
pos: i+2,
msg: "This does not mean what it looks like. You may be forgiven to think that the full string of \
numerals is the variable name. Only the fist is.\n\
\n\
Try this and be shocked: f() { echo \"$9\" \"$10\"; }; f a b c d e f g h i j\n\
\n\
Here is where braces should be used to disambiguate, \
e.g. \"${10}\" vs \"${1}0\".\n\
\n\
Syntactic pitfalls are deemed too dangerous to fix automatically\n\
(the purpose of Shellharden is to fix brittle code – code that mostly \
does what it looks like, as opposed to code that never does what it looks like):\n\
* Fixing what it does would be 100% subtle \
and might slip through code review unnoticed.\n\
* Fixing its look would make a likely bug look intentional."
});
} else if c == b'@' || c == b'*' || (c >= b'0' && c <= b'9') {
} else if c == b'@' || c == b'*' || is_decimal(c) {
if predlen(&is_decimal, &horizon[i+1 ..]) > 1 {
return bail_doubledigit(horizon, i+2);
}
let ext = Box::new(SitExtent{
len: 2,
color: COLOR_VAR,
@ -213,3 +196,25 @@ fn pos_tailhazard(horizon: &[u8], end: u8) -> (usize, usize) {
fn is_decimal(byte: u8) -> bool {
byte >= b'0' && byte <= b'9'
}
fn bail_doubledigit(context: &[u8], pos: usize) -> CommonStrCmdResult {
CommonStrCmdResult::Err(UnsupportedSyntax {
typ: "Unsupported syntax: Syntactic pitfall",
ctx: context.to_owned(),
pos,
msg: "This does not mean what it looks like. You may be forgiven to think that the full string of \
numerals is the variable name. Only the fist is.\n\
\n\
Try this and be shocked: f() { echo \"$9\" \"$10\"; }; f a b c d e f g h i j\n\
\n\
Here is where braces should be used to disambiguate, \
e.g. \"${10}\" vs \"${1}0\".\n\
\n\
Syntactic pitfalls are deemed too dangerous to fix automatically\n\
(the purpose of Shellharden is to fix brittle code – code that mostly \
does what it looks like, as opposed to code that never does what it looks like):\n\
* Fixing what it does would be 100% subtle \
and might slip through code review unnoticed.\n\
* Fixing its look would make a likely bug look intentional."
})
}