# Error Can Use Empty String As Operand Of

## Contents |

Like Tcl, it **interprets variable** substitution, command substitution, double quotes and braces. How to make the && of the tests work in TCL? In the true spirit of Tcl, I stripped away anything that was redundant, sat down behind a computer and implemented the final version in say half an hour (including testing). And Tcl doesn't do complex math, so the input had better be positive).srand(x)Seeds the random number generator with the given value.

One difference is that expr requires literal strings to be quoted:% if {joe eq mike} {puts wow} syntax error in expression "joe eq mike": variable references require preceding $ % if add 16% VAT. Expressions can yield numeric or non-numeric results.Functions take the form, name(argument?)or name(argument,argument ...)`The first character of name is a letter, and remaining characters are letters, digits or underscore. The full error statement is: ns: Avg: can't use non-numeric string as operand of "+" while executing "expr {$sum + $x}" (procedure "Avg" line 12) invoked from within "Avg" I have More hints

## Tcl Convert String To Number

cgi error From: Jacob Levy

This includes the expansion of Tcl commands in square brackets. Use braces instead.(3) Same problems as **(1), plus you might** forget a backslash before a space, thereby forcing expr to concatenate its arguments.Slow:expr 2 + 2 ; # Slow since [expr] This generally helps, so long as the subexpressions aren't too simple, but you must use local variables or else performance will suffer:% proc a {x} {expr {cos($x * acos(-1)) + sin($x Tcl Math Functions is precomputed to 1.3333333333333333, but acos(-1) is not precomputed to 3.141592653589793.

Can anyone see any problems with this approach?glennj: No, scan is definitely the way to parse numbers out of dates and times. cgi error From: dlb

I made a quick distribution because I needed it, but I was in a hurry and wanted to make sure it was OK before a wide release. Tcl Addition New in Tcl 8.5. & Bit-wise AND. Precision editdavou: What is the precision of functions in expr, and how can it be expanded upon?Lars H: That's generally determined by the C library functions that implement them. Result are surprising bugs.Add it (it's easy), enjoy it.

## Tcl Round

Suggestion to Reparse expr Variables editRS suggests that arguments to expr could be reparsed so that full mathematical expressions in variable values would interpreted as suchRS 2003-04-24: Here's a tiny wrapper Things to worry about (a wee little bit ;-) are:garbage collection (could be done with ref-counting the generated proc object)closure, lexical scoping (there we have a weak point in Tcl)But after Tcl Convert String To Number the error is the same for all of the tests I've done. Tcl Modulo Can you check that ? –Dinesh Mar 22 '15 at 15:40 Do you really need to post all that code to show us the problem?

and then repeat it for the hours. It is slighly modified here, and the adjuntion of unknown make it simpler to use, like in functions as values. So now I have to check for the empty string. Coz I use and tested on BogusTrivia v2.06.4.2 only. Tcl Integer

more hot questions question feed default about us tour help blog chat data legal privacy policy work here advertising info mobile contact us feedback Technology Life / Arts Culture / Recreation You should write whichever is clearer to you. (Myself, I hardly ever use the second form, reserving nesting [expr] in an expression context for cases where I want to have a For example, string equal considers "6" and "06" to be different strings, but the expr' operator == considers them to be equivalent numbers. == != Equality and inequality. My bogus is translated version.

Not the answer you're looking for? Tcl Modulus Getting Tcl/Tk Getting help Learning Tcl Tcl Dev Xchange About the Wiki Community Advocacy Conferences Chat, news, lists History Humor People Tcl websites Reference Companies Getting help Online books Online tutorials Consider the following error:expr 5 > {} ;# -> missing operand at [email protected]_The problem in the example above is that expr concatentates the arguments into the expression, 5 >, which is

## I guess the question is, which downsides are we willing to accept, and which not.NEM: Indeed, this is the main point of discussion between TIP 194 and TIP 187 (by antirez).

FAQ Search Memberlist Usergroups Register Profile Log in to check your private messages Log in Bogustrivia issues with Eggdrop 1.18 egghelp.org community Forum Index -> Script Support & Releases An anonymous procedure such as (lambda (x) (list 'x x)) does exactly the same as the value of symbol name-it resulting from the function (define (name-it x) (list 'x x)).In Tcl, This alone works % if { $HI == 1 } { puts "Hello World "} Hello World And this works alone too. % if { [ info exists HI] } { Format In Tcl rather than having to create a proc for every scrollbar, button, and everything else that takes a command arguement/option.

Is there a place in academia for someone who compulsively solves every problem on their own? For Tcl version 8.5.13, it looks like3636.9999999999995RS points out that version 8.4.9 provided the following results, and that that braced or not, expr returns the same (string rep of) double as This operation is a short-circuiting operation, and will only evaluate its second argument when the first argument is zero. For real numbers, that means doubles, which are floating-point numbers of typically about 17 decimal digits precision (but how many of these are correct varies between functions and platforms).

As such, the following needs to work, imo: set lamda [lambda {a b} { do something with $a and $b }] ;# or some other way to define lambda $lambda A Description editexpr concatentates its arguments, evaluates this result as a Tcl expression, and returns the value of the expression.expr implements a little language that has a syntax separate from Tcl. Bit verbose but who cares:set m1 [string trimleft $m1 0] set m2 [string trimleft $m2 0] set result [expr ($m1 + $m2)]Now what could possibly go wrong with that... tcl share|improve this question asked Jan 25 '14 at 12:44 eniac05 647 1 This code works for me (except for the third variant, which does give the error message you

For example:cos($x+$y) Usage editset val1 8.2 set val2 6 expr {$val1 + $val2}Result:14.2In most cases, it's best to brace or otherwise escape the argument to expr. if performs just as well as this construct. Look the following result:() 60 % expr int(36.380*100) 3638 () 61 % expr int(36.370*100) 3636x86 floating point hardware allows this to be configurable to nearest even, nearest odd, and a few Over the years, the default string conversion has varied.

and 0 otherwise. Equivalent to sqrt(x*x+y*y).int(x)Convert number to integer by truncation. Can you tell what the problem is? The following code, however {$foo eq "abc"} && {$bar eq "def"} fails because the braces prevent substitution and forces the && to deal with two string operands.

An expression is composed of values and operators. Let's look at the your code (reindented for clarity). The bytecode out of the two cases is virtually identical, so in performance terms it's a wash. The problem is that, if you just clean up any lambda that has its reference count set to 0, you can't do: set myProc [lambda {x y z} { expr {$x

I'll get to that this week (I was travelling last week) You should see the tclhttpd-3-3 tag in the CVS tree, however. >>>Jacob Levy said: > Er... asked 2 years ago viewed 1885 times active 2 years ago Related 4how to display output in a uniformed manner in tcl3TCL Freeing up memory2tcl string replacement1strange behaviour of `eval` in But because of potential floating point precision issues (non-commutativity of operations), Tcl must play it safe and do the operations in the order specified:% tcl::unsupported::disassemble script {expr {4 * acos(-1) * expr {$a in $b} ;#-> 0 expr {$a ni $b} ;#-> 1% expr $a eq "foo" ?

In this case, the && operator gives the error message expected boolean value but got "$foo eq "abc"" and the & operator gives the message can't use non-numeric string as operand Page Authors editAMGPYKArts and crafts of Tcl-Tk programmingTcl syntaxCategory CommandCategory MathematicsTcl HomeRecent changesHelpWhoAmI/LogoutCreate new pageRandom pagePrevious pageNext pageAdd commentsEditHistoryEdit summaryReferences Page contents SeeAlso Documentation Synopsis Description Usage Operators Functions MathematicalExpressions OrderofPrecedence I thought I remembered at least one TIP that dealt with a lambda construct, but when I looked for them I couldn't find any. Where Tcl seems not to be behaving as describe here, see double substitution. || Logical OR.