tcl

Tcl Tcl TutorialTutorial

Tcl Tutorial Oct-2000

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OutlineOutline

q Tcl Tutorial

q Outline

q What is Tcl ?

q What is Tk ?

q Why is Tcl that successful ?

q When using Tcl ?

q Why is Tcl better than ...?

q Tcl Extensions

q Getting started

q Example !Compute factorial

q Tcl Fundamentals

q Tcl Basics

q Comments

q Mathematical Expressions

q Control Structures

q Strings

q Lists

q Arrays

q Procedures

q File-IO

q Wildcards (glob)

q Regular expressions

q Error handling

q Different stuff

q Advanced Concepts

q TCL-Reference

q Tcl & EDA Market


- Slide 3 -

What is What is TclTcl ??

q Tool Command Language ( tickle )" #

q Scripting language

n simple syntax

q Library package

n can be embedded in applications

n language parser

n build in commands

n extensible


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What is What is TkTk ??

q Graphical user interface toolkit.

q Tk is portable.

q Tk is easy to use.

q Tk allows rapid development.

q Tk implements platform look and feel on UNIX, Windows and Mac.

q lsivega graphical user interface is 1 00% Tk.


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Why is Tcl that successful ?Why is Tcl that successful ?

q Tcl provides programmability.

q Tcl application needs to implement only application specific low level commands.

q Tcl is a Vendor independent standard.

q Tcl is easy to learn.

q Tcl is a complete language.

q Tcl is complete royalties free.

q Tcl and Tk are highly portable.

q Tcl supports rapid development.

q Tcl makes your application extensible.


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When using When using TclTcl ??

q Philosophy large software should use two languages :" #

1 . system language

§ manipulating complex internal data structures

§ performance is key

2. scripting language

§ tie pieces together

§ provide user interface


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Why is Tcl better than . . .?Why is Tcl better than . . .?

F e a tu re s (w w w . s c r i p t i c s . c om ) T c l P e r l P y th o n J a v a S c r i p t

V i s u a l B a s i c

Ra p i d d e ve l o pm e n t ü ü � ü � ü � ü �

F l e x i b l e , ra p i d e v o l u t i o n

ü � ü � ü � ü � ü �

I n te ra c t i v e S h e l l ü �

S p e e d o f u s e

G re a t re g u l a r e x p re s s i o n s

ü � ü ü �

E a s i l y e x te n s i b l e ü � ü � ü

Em b e d d a b l e ü � ü �

E a s y G U I s ü � ( Tk ) ( T k) ü �

B re a d th o f fu n c t io n a l i ty

I n te rn e t re a d y ü � ü � ü � ü � ü �

C ro s s p l a tfo rm ü � ü � ü � ü �

Th re a d s a fe ü � ü � ü �

D a ta b a s e a c c e s s ü � ü � ü � ü � ü �

O b j e c t o r i e n te d ü ( iT c l ) ü � ü � ü � ü �

E n te rp r i s e u s a g e

M a in ta i n a b i l i ty ü ü � ü � ü �

�

�


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Tcl ExtensionsTcl Extensions

q Graphical user interface

q Object system

q Automating interactive applications

q Networking

q Database access


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Getting startedGetting started

q How to make run-able Tcl scripts:

n Create a text fi le which starts with#!<path to>/tclsh or if Tk is needed #!<path to>/wish

n Or if the path to the Tcl interpreter is unknown#! /bin/sh# following line is a comment for Tcl but not for sh# \exec tclsh $0 $@" #

n Make your script executable (chmod)

n Or source your script in a tclsh/wishtclshsource my_script. tcl


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Example Example !! Compute factorialCompute factorial

proc factorial { x } {set product 1

for { set i 1 } { $i <= $x } { incr i } {set product [ expr { $product * $i } ]

}return $product

}

proc factorial_recursive { x } {if { $x == 1 } {

return 1} else {

return [ expr { $x * \[ factorial_recursive [ expr { $x -1 } ] ] } ]

}}

puts "fact(10) = [ factorial 10 ] #puts "fact(10) = [ factorial_recursive 10 ] "


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Tcl FundamentalsTcl Fundamentals

q String based language - Everything is a string !

q Only a few constructs.

q Simple syntax.

q Tcl is interpreted.

q Tcl knows only two language constructs:

n commands

n variables


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q The concept of Tcl is a l ittle different than other languages

it s worth to understand the basic concepts !$

q Variables

q Commands

q Grouping

q Substitution

q Command call

Tcl BasicsTcl Basics


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Tcl Basics Tcl Basics -- VariablesVariables

q Set command is used to assign a valueset variable 2000

q The dollar sign $ is used to obtain the value from a variable.puts $var

q Case is significant for variable names.

q Variable names can contain any character and be of any length.

q Variables defined outside any procedure are global variables.

q Global variables are not automatically visible inside procedures.-> use global variable-name to make them accessible

q Variables don t need to be declared.$


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Tcl Basics Tcl Basics -- CommandsCommands

q A Tcl script is a sequence of commands.

q Basic syntax for a Tcl command:command-name arg1 arg2 arg3 . . .

q White spaces (space or tabs) separate command name and arguments.

q Newline or semicolon terminates a command.

q A command returns one string.


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Tcl Basics Tcl Basics -- GroupingGrouping

q Curly braces { } prevent substitution.

q Double quotes " # allow substitution.

q \ escapes white spaces (space, tabs, newlines).

q Braces { } and quotes " # are not part of the value.


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Tcl Basics Tcl Basics -- SubstitutionSubstitution

q Backslash substitution \

n Quotes special characters l iterally.

n Specify hexadecimal or octal values.

q Variable substitution $

n Substitute variable by value.puts $varset a \$bc; puts $a ; # -> $bc

q Command substitution [ ]

n Nesting commands.puts [ string length Hi " lsiVega# ]


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Tcl Basics Tcl Basics -- ExecutionExecution

q Execution calls the command passing all arguments.

q Command returns a value or an error.


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Example Example !! Compute factorialCompute factorial

proc factorial { x } {set product 1

for { set i 1 } { $i <= $x } { incr i } {set product [ expr { $product * $i } ]

}return $product

}

proc factorial_recursive { x } {if { $x == 1 } {

return 1} else {

return [ expr { $x * \[ factorial_recursive [ expr { $x -1 } ] ] } ]

}}

puts "fact(10) = [ factorial 10 ] #puts "fact(10) = [ factorial_recursive 10 ] "


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CommentsComments

q Comments in Tcl starts with the hash character #.

q The hash character must occur at the beginning of a command.

q The semicolon ; can be used to terminate the previous command.

set a 1 ; # I m a comment$

q Comments can be continued to the next l ine escaping the newline

# I m a long $ \comment


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Mathematical ExpressionsMathematical Expressions

q Evaluation of a mathematical expressionexpr arg arg . . .

q All arguments are concatenated together and evaluated as a Tcl expression.

q Expressions are subject of two rounds of substitutions!

n one by the Tcl interpreter

n one by expr itself

protect expressions with curly braces


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Mathematical ExpressionsMathematical Expressions

q Works with boolean, integer, double and strings.

q + - * / % ~ & | ^ ! && | | << >> < > <= >= == != ?:

q sin cos tan abs log sqrt ...

q Examplesexpr { 5 / 4 } ; # -> 1expr { 5 / 4. 0 } ; # -> 1. 25expr { 5 / ( 4 + 0. 0 ) } ; # -> 1. 25expr { a == g } ; # " # " # -> 0expr { a == g } ; # -> syntax errorexpr { asin(1) * 2 } ; # -> 3. 14159265359


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Control StructuresControl Structures

q Conditional commands

n if then else

n switch

q Loops

n while

n for

n foreach

n break, continue

q Others

n return, error, catch


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Control Structures Control Structures -- Conditional Conditional CmdCmd

q if: if test1 body1 elseif test2 body2 % else body3

if { $var == 3 } {puts "var is equal to 3#

} else {puts "var is different of 3#

}


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Control Structures Control Structures -- Conditional Conditional CmdCmd

q switch: switch flags value pattern1 body1 pattern2 body2 ...

switch -regexp -- $var {"hu. * # -"foo. * {#

puts "var starts with hu or with foo#}" #. *bar {

puts "var ends with bar#}default {

puts "var is $var#}

}


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Control Structures Control Structures -- LoopsLoops

q while loop: while test bodyset i 0while { $i < 10 } {

puts $iincr i

}

q for loop: for start test next bodyfor { set i 0 } { $i < 10 } { incr i } {

puts $i}

q loop flow: break, continuebreak causes immediate exit from the loop while continue causes the loop to go over to the next iteration.


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Control Structures Control Structures -- Loops Loops -- foreachforeach

q simple foreach: foreach varname list body

foreach var { a b c d } {puts $var

}

q foreach loop: foreach varlist1 list1 ?varlist2 list2 . . . ? body

foreach { var value } { a 1 b 2 c 3 } {puts $" var is $value#

}


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StringsStrings

q


- Slide 28 -

StringsStrings

q String length: string length stringstring length Hi " lsiVega# ; # -> 10

q String indexing: string index string indexstring index Hi " lsiVega# 4 ; # -> s

q String matching: string match pattern stringstring match Hi * Hi " # " lsiVega# ; # -> 1

q Lower/upper case: string tolower string ; string toupper stringstring tolower "Hi lsiVega# ; # -> hi lsivega

q Trim string: string trim string ?chars? ; string trimleft / trimrightstring trim Hi " lsiVega# " agi# ; # -> Hi lsiVe


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StringsStrings

q String search: string first search-string string ; string last

string first "lsi# " Hi lsiVega# ; # -> 3

q Sub-String extraction: string range string first laststring range Hi " lsiVega# 3 end ; # -> lsiVega

q String comparing: string compare ?-nocase? string1 string2

string compare Hi Hi" # " lsiVega# ; # -> -1

q Appending strings: append var-name value value ...

set var " #Hiappend var "lsiVega#; puts $var ; # -> HilsiVega


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StringsStrings

q String formating: format format arg arg ...

format "-%20s %. 4f-# " abc# 1. 987654321

; # -> - abc 1. 9877-

q Parsing strings: scan string format var var . . .

scan "abc 1. 9877 %s %f var1 var2 ; # # " # -> 2puts $var1 ; # -> abcputs $var2 ; # -> 1. 9877


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ListsLists

q A Tcl l ist is a Tcl string with l ist elements separated by spaces.

q List elements are grouped like command arguments.

q List operations are fast in Tcl.


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ListsLists

q Building lists: list value value . . .set x { d e}set l1 [ list a $x b c ]" # ; # -> a { d e} { b c}

n the l ist command does automatic quoting

q Appending elements to l ists: lappend list value value . . .lappend l1 g f ; # -> a { d e} { b c} g f

q Indexing lists: lindex list indexlindex $l1 2 ; # -> b c


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ListsLists

q Sorting lists: lsort -integer|-dictionary|... listlsort $l1 ; # -> a { b c} { d e} f g

q Length of l ists: llength listllength $l1 ; # -> 5

q Searching in l ists: lsearch -exact|-glob|-regexp list patternlsearch $l1 f ; # -> 3

q Concatenate lists: concat list list . . .concat $l1 f $l1

; # -> a { d e} { b c} g f f a { d e} { b c} g f


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ListsLists

q Merge elements of a l ist: join list join-stringset a [ join $l1 / ] ; # -> a/d e/b c/g/f

q Spliting list in elements: split list split-characterssplit $a / ; # -> a { d e} { b c} g f

q Extract sub-list: lrange list first lastlrange $l1 2 3 ; # -> { b c} g

q Replace elements: lreplace list first last element element . . .lreplace $l1 2 3 q ; # -> a { d e} q f

q Insert elements into l ist: linsert list index element element . . .linsert $l1 2 w ; # -> a { d e} w { b c} g f


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ArraysArrays

q Variable with an string typed indexset my_array(my_index) I m an array value" $ #

puts $my_array(my_index)

q array <subcommand>

n array names arr ?pattern? returns index names matching pattern

n array get arr ?pattern? return index/value pairs

n array set arr key1 value1 key2 value2 . . . ? what does this?

q Multidimensional arraysset field($x, $y) $value


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Looping over arraysLooping over arrays

q Converting array into a l istset volt(best) 2. 75;set volt(nom) 2. 5;set volt(worst) 2. 25foreach voltage [ array names volt ] {

puts $voltage: $volt($voltage)" #

}

q Converting array into a double-listset volt(best) 2. 75;set volt(nom) 2. 5;set volt(worst) 2. 25foreach { voltage value } [ array get volt ] {

puts $voltage: $value" #

}


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Data structures using arraysData structures using arrays

q Records:set name Roland" #

set people($name, phone) +39/039/6573736" #

set people($name, group) FDM" #

foreach key [ array names people(Roland, *) ] {puts $people($key)" #

}

q Stacks

q List of arrays


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ProceduresProcedures

q proc name arguments bodyproc print { msg1 msg2 } {

return $msg1 $msg2" #

}

print Hello Ciao ; # -> Hello Ciao

q Default argumentsproc inc { var { value +1 } } { . . . }

q Variable number of argumentsproc print { msg args } { puts $" msg $args# }

print Hi lsi vega 2000 ; # -> Hi lsi vega 2000


- Slide 39 -

ProceduresProcedures

q Create link to variable in a different stack frameupvar ?level? other-var myvar

proc sample { table_var } {upvar $table_var table

puts [ array get table ]}

array set ary a 1 b 2 c 3sample ary


- Slide 40 -

FileFile--IOIO

q file <sub-command>

n fi le mkdir creates a d irectory

n fi le exists checks whether or not a fi le/directory exists

n fi le rename renames a fi le/directory

n fi le d irname returns the parent d irectory of the given fi le name

n fi le delete deletes a fi le/directory

n fi le copy copies fi les

n many more . . .


- Slide 41 -

FileFile--IOIO

q Open file: open filename ?mode? ?permissions?set fileid [ open ." cshrc# " # w ] ; # opens fileset fileid [ open | sort ." cshrc# " # r ] ; # opens pipe

q Close file: close fileidclose $fileid

q Read from file: gets fileid varname ; read ?-nonewline? fileidwhile { [ gets $fileid line ] >= 0 } { . . . }set data [ read $fileid ]

q Write to file: puts ?-nonewline? ?fileid? stringputs $fileid "Hi lsiVega#


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Wildcards (glob)Wildcards (glob)

q Globbing is used for simple string (string match, lsearch, switch) and file (glob) matching.

n ? Matches any single character

n * Matches any sequence of zero or more characters.

n [chars] Matches any single character in chars. I f charscontains a sequence of the form a-b then any characterbetween a and b (inclusive) wil l match.

n {a,b, . . . } Matches any of the strings a, b, etc.

q Tcl wildcards are similar to sh/csh wildcards

n but no sorting

n csh doesn t check for existence unless the pattern contains ?, * or $ [ ] (try echo aaa versus echo aaa*)


- Slide 43 -

Regular expressionsRegular expressions

q Regular expressions are used for more sophisticated string matching.

q New advanced regular expressions in Tcl 8.1 .


- Slide 44 -

Regular expressions Regular expressions -- PatternsPatterns

q Pattern basicsn . Matches any single character

n [chars] Matches any single character in chars.Supports range of characters [a-b] .Supports negation of character set [^. . . ]

n * Matches 0 or more of the previous pattern.

n ? Matches 0 or 1 of the previous pattern.

n + Matches 1 or more of the previous pattern.

n ^ Matches only at the start of a string.

n $ Matches only at the end of a string.

n () Groups pattern.

n | Matches just one alternative (or).

n \ Escapes special characters.


- Slide 45 -

Regular expressions Regular expressions -- regexpregexp

q regexp ?switches? pattern string ?match-var? ?sub-match-var?...

n compares a string to a regular expression

n returns 1 of the expression matches, otherwise it returns 0

n it stores the matched part of the string in match-var

n it stores subparts of the matched string in sub-match-var

n switches -nocase, -all or many others (see man-page)

q Example:set display muncs18: 0. 1regexp { ([^: ] *) : [0-9] +} $display match submatch1 ; # -> 1puts $match ; # muncs18: 0puts $submatch1 ; # muncs18


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Regular expressions Regular expressions -- regsubregsub

q regsub ?switches? pattern string substitute-expression var

n substitutes matching parts of a string with a substitute-expression

n returns the number of replaced strings

n it stores the new string in var

n switches -nocase, -all or many others (see man-page)

n & (or \0) wil l be replace with the portion of the string which matches pattern

n \1 . . . \9 wil l be replaced with the portion of the string which matches the 1 st . . 9th group

q Example:set display muncs18: 0. 1regsub { ([^: ] *: ) [0-9] +} $display { \14} var ; # -> 1puts $var ; # muncs18: 4. 1


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Advanced regular expressionsAdvanced regular expressions

q non-greedy matching

n * and + make regexps matching as much text as possible

n adding a ? after the qualifier makes them matching the least text they canset line { a b c }" # " # " #

regexp { . * } $line " # var; puts $var ; # -> a b c" # " # " #

regexp { . *? } $line" # var; puts $var ; # -> a" #

q backslash escapes

n are now interpreted by the regexp engine itselfregexp { [a-z] \n} instead of regexp "\[a-z\] \n#


- Slide 48 -


q back-references

n matches the same string that was matched by a previous groupregexp { ^(. *) \1$} $line

; # matches double words sep. with space

q constraint escapes

n constraints an regexp to match only at a certain place\m matches only at the start of a word

q internationalization

n character classes[[:digit: ]] or \d matches one d igit[[:alpha: ]] matches one letter but includes also special languagecharacters (german ä, spanish ñ and many more [a-z] does notcover)


- Slide 49 -


q Bounds

n new quantifiers allow to specify how many time the previous partmust be repeated in order to match (extension of ?, * and +){m} allows exactly m repetitions{m, } allows m or more repetitions{m,n} allows at least m but not more than n repetitions


- Slide 50 -

Error handlingError handling

q Generating an error: error message

error $opt is not a legal option" #

q Trap errors: catch tcl-commands ?var?

if { [ catch { open $filename r } " # msg ] } {puts Can not open file $filename , got $" & $ & msg$ . #

}

q Getting stack trace after an error: puts $errorInfo


- Slide 51 -

Different stuffDifferent stuff

q Load a Tcl script source filename

q Exit the Tcl shell exit

q Get the history of commands typed history

q Get information about Tcl internals info option

q Make a system call exec args

q Evaluate a string as a Tcl command eval args

q Perform backslash, command, and variable substitutions subst

q Change directory cd

q Get working directory pwd


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Advanced ConceptsAdvanced Concepts

q namespace

q socket

q uplevel/upvar

q multiple interpreters/safe interpreters

q binary file handling

q threads


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TCLTCL--ReferenceReference

http: //dev. scriptics. com/man/


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Tcl & EDA MarketTcl & EDA Market

q Synopsys Formality, Primetime, newer Design Compiler

q Ambit Buildgates

q Mentor Modelsim

q LSI lsivega

q and many other EDA tools and it expands fast

q It may be useful to have a basic understanding of Tcl! !

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