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author | dkf <donal.k.fellows@manchester.ac.uk> | 2012-05-16 23:16:14 (GMT) |
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committer | dkf <donal.k.fellows@manchester.ac.uk> | 2012-05-16 23:16:14 (GMT) |
commit | 03716dfee8f0f0df26a8c56e6a2b3ceeb9319dbc (patch) | |
tree | 2f319240c63b52f71ee8329acb2dac92452ed23b | |
parent | 7ac6053161fe49bc32f962b38e67f94f172ce709 (diff) | |
download | tcl-03716dfee8f0f0df26a8c56e6a2b3ceeb9319dbc.zip tcl-03716dfee8f0f0df26a8c56e6a2b3ceeb9319dbc.tar.gz tcl-03716dfee8f0f0df26a8c56e6a2b3ceeb9319dbc.tar.bz2 |
[Bug 3525462]: Document what relational operators really do with string args.
-rw-r--r-- | ChangeLog | 6 | ||||
-rw-r--r-- | doc/expr.n | 6 |
2 files changed, 9 insertions, 3 deletions
@@ -1,3 +1,9 @@ +2012-05-17 Donal K. Fellows <dkf@users.sf.net> + + * doc/expr.n: [Bug 3525462]: Corrected statement about what happens + when comparing "0y" and "0x12"; the previously documented behavior was + actually a subtle bug (now long-corrected). + 2012-05-13 Jan Nijtmans <nijtmans@users.sf.net> * win/tclWinDde.c: Protect against receiving strings without ending \0, @@ -364,6 +364,7 @@ returns \fB4.0\fR, not \fB4\fR. String values may be used as operands of the comparison operators, although the expression evaluator tries to do comparisons as integer or floating-point when it can, +i.e., when all arguments to the operator allow numeric interpretations, .VS 8.4 except in the case of the \fBeq\fR and \fBne\fR operators. .VE 8.4 @@ -374,11 +375,10 @@ a string using the C \fIsprintf\fR format specifier For example, the commands .CS \fBexpr {"0x03" > "2"}\fR -\fBexpr {"0y" < "0x12"}\fR +\fBexpr {"0y" > "0x12"}\fR .CE both return 1. The first comparison is done using integer -comparison, and the second is done using string comparison after -the second operand is converted to the string \fB18\fR. +comparison, and the second is done using string comparison. Because of Tcl's tendency to treat values as numbers whenever possible, it isn't generally a good idea to use operators like \fB==\fR when you really want string comparison and the values of the |