Tool Command Language (Tcl) is a scripting language used to build applications. Tcl scripts are made up of commands with arguments separated by whitespace. Common uses of Tcl include web servers, desktop GUIs, networking, and testing. Tcl has basic control structures like if/else, for loops, and while loops. Special variables like argc and argv are used to access command line arguments. File I/O is done using the open, gets, and puts commands. Regular expressions can be used to search text with the regexp command.

1. TOOL COMMAND LANGUAGE
or
TICKLE

2. • It is dynamic languages
• Tcl is a scripting language
• Tcl own interpreter
• Tcl commands have executed line by line
• Tcl extension is .tcl
• One or more words separated by white space
• First word is command name, others are arguments

3. Applications
• Tcl is a general-purpose language
• High performance web servers build with TclHttpd
• Scalable websites backed by databases
• EDA
• CAD
• Desktop GUI applications
• Networking
• Administration
• Testing
• Embedded applications

4. Command
• words separated by whitespace
• First word is a function, others are arguments
• Only functions apply meanings to arguments
• Single-pass tokenizing and substitution
• $ causes variable interpolation
• [ ] causes command interpolation
• “” prevents word breaks
• { } prevents all interpolation
• escapes special characters
• TCL HAS NO GRAMMAR!

5. Examples
Set a vlsiguru
Puts “my institute name is $a”
Puts {my institute name is $a}
Output
my institute name is vlsiguru
my institute name is $a

6. Sample command Result
set a 900
set b 99
set c [expr $a +$b] 999
puts $c
set c [expr $a -$b] 801
puts $c
set c [expr $a *$b] 89100
puts $c
set c [expr $b /$a] 100
puts $c
set c [expr ($a % $b)] 0
puts $c

7. List Operators and Syntax
1. Lindex example: set a [blue yellow red]
2. Llength set b [lindex $a]
3. Linsert
4. Lrange
5. Lreplace
6. Lset
7. Lsort
8. Lsplit
9. concat
10.Lassign example: set a [blue yellow red]
11.Lappend lassign $a b y r

8. Control Structures
• Just commands that take Tcl scripts as arguments.
• “ – “
• Commands:
for while if
break continue
expr int ceil
real nocase
foreach switch string
proc return flag
arrays dict

9. Syntax of the FOR loop
for {initaization} {condition} {incr/decr} {
body of the for loop
}
for {set i 1} {$i<=5} {incr i} {
puts $i
}

10. Syntax of the WHILE loop
initaization
while {condition} {
body of the for loop
incr/decr
}
set i 10
while {$i>10} {
puts $incr i -1
}

11. Synatx of if statement
• if {condtion} {
• body of if statement
• }
• if {cond-1} {
• body of statement-1
• } else if {cond-2} {
• body of else if statement
• } else {cond} {
• body of else statment
• }

12. example of if statement
for {set i 1} {$i<=50} {incr i} {
if {$i %2 != 0} {
puts $i
}
}

13. break continue
set i 1 set i 1
while {$i <= 15} { while {$i <= 15} {
if {$i == 5} { if {$i == 5} {
break incr i
} continue
incr i }
puts $i incr i
} puts $i
}

14. Special variables in Tcl
Argc : Count of the arguments.
argv : Display the values of the arguments.
argv0 : Display the tcl file name
# rudra.tcl 9 39 69 99
puts "countb of the argument:$argc"
puts "value of the arguments:$argv"
puts "display the tcl file name :$argv0"

15. FILE HANDLING OPERATION
Syntax for file handling operations
Set variables [open "filename.extension" accessmode]
puts $variables
set r [open “rudra.tcl" r] #Read
Puts $r
set w [open “text.tcl" w] #write
Puts $w “"welcome to Garden city India"
set a [open “rudra.tcl" a] #append
puts $a "welcome to vlsiguru"

16. Regular Expressions
The "regexp" command is used to match a regular expression
in TCL.
Regular expression is a sequence of characters that contains a
search pattern
Syntax :regexp { } {
}

17. set fhr [open "VHDL.txt" r]
Puts $fhr
set fhr [open "VHDL.txt" r]
while {[gets $fhr line] >= 0} {
Puts $fhr
}
set fhr [open "VHDL.txt" r]
set i 0
while {[gets $fhr line] >= 0} {
incr i
Puts $fhr
Puts line number $i

18. set fhr [open "VHDL.txt" r]
set i 0
set j 0
while {[gets $fhr line] >= 0} {
incr i
if {[regexp -nocase { *entity +([a-z0-9_]*) +} $line temp en]} {
incr j
puts $temp
puts $en
puts "file line number:$i number of times:$j entity_name:$en"
}
}

19. Thank you