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authorLuis Custodio <luis.custodio@gmail.com>2015-10-17 13:11:25 +0200
committerLuis Custodio <luis.custodio@gmail.com>2015-10-17 13:11:25 +0200
commitf5873b08901bfaec3fb46518258ff9e886fd04c4 (patch)
tree62886b71c7226f0c6c4f979d61ff96c839a641a9 /tcl.html.markdown
parentc9348e5a82b639093f8f3eee955ffdf6fb99b5d8 (diff)
parent0e6d9f6fe9aeffc64c3adad3e4a0ee1cc0d1dd88 (diff)
Merge branch 'master' of github.com:adambard/learnxinyminutes-docs
Diffstat (limited to 'tcl.html.markdown')
-rw-r--r--tcl.html.markdown48
1 files changed, 24 insertions, 24 deletions
diff --git a/tcl.html.markdown b/tcl.html.markdown
index 3982807f..b90bd690 100644
--- a/tcl.html.markdown
+++ b/tcl.html.markdown
@@ -14,7 +14,7 @@ programming language. It can also be used as a portable C library, even in
cases where no scripting capability is needed, as it provides data structures
such as dynamic strings, lists, and hash tables. The C library also provides
portable functionality for loading dynamic libraries, string formatting and
-code conversion, filesystem operations, network operations, and more.
+code conversion, filesystem operations, network operations, and more.
Various features of Tcl stand out:
* Convenient cross-platform networking API
@@ -58,14 +58,14 @@ lighter that that of Lisp, just gets out of the way.
#! /bin/env tclsh
################################################################################
-## 1. Guidelines
+## 1. Guidelines
################################################################################
# Tcl is not Bash or C! This needs to be said because standard shell quoting
# habits almost work in Tcl and it is common for people to pick up Tcl and try
# to get by with syntax they know from another language. It works at first,
# but soon leads to frustration with more complex scripts.
-
+
# Braces are just a quoting mechanism, not a code block constructor or a list
# constructor. Tcl doesn't have either of those things. Braces are used,
# though, to escape special characters in procedure bodies and in strings that
@@ -73,7 +73,7 @@ lighter that that of Lisp, just gets out of the way.
################################################################################
-## 2. Syntax
+## 2. Syntax
################################################################################
# Every line is a command. The first word is the name of the command, and
@@ -83,13 +83,13 @@ lighter that that of Lisp, just gets out of the way.
# are used, they are not a string constructor, but just another escaping
# character.
-set greeting1 Sal
+set greeting1 Sal
set greeting2 ut
set greeting3 ations
#semicolon also delimits commands
-set greeting1 Sal; set greeting2 ut; set greeting3 ations
+set greeting1 Sal; set greeting2 ut; set greeting3 ations
# Dollar sign introduces variable substitution
@@ -126,11 +126,11 @@ puts lots\nof\n\n\n\n\n\nnewlines
set somevar {
This is a literal $ sign, and this \} escaped
brace remains uninterpreted
-}
+}
# In a word enclosed in double quotes, whitespace characters lose their special
-# meaning
+# meaning
set name Neo
set greeting "Hello, $name"
@@ -178,7 +178,7 @@ set greeting "Hello $people::person1::name"
################################################################################
-## 3. A Few Notes
+## 3. A Few Notes
################################################################################
# All other functionality is implemented via commands. From this point on,
@@ -193,8 +193,8 @@ set greeting "Hello $people::person1::name"
namespace delete ::
-# Because of name resolution behaviour, it's safer to use the "variable" command to
-# declare or to assign a value to a namespace. If a variable called "name" already
+# Because of name resolution behaviour, it's safer to use the "variable" command to
+# declare or to assign a value to a namespace. If a variable called "name" already
# exists in the global namespace, using "set" here will assign a value to the global variable
# instead of creating a new variable in the local namespace.
namespace eval people {
@@ -210,7 +210,7 @@ set people::person1::name Neo
################################################################################
-## 4. Commands
+## 4. Commands
################################################################################
# Math can be done with the "expr" command.
@@ -295,7 +295,7 @@ while {$i < 10} {
# A list is a specially-formatted string. In the simple case, whitespace is sufficient to delimit values
-set amounts 10\ 33\ 18
+set amounts 10\ 33\ 18
set amount [lindex $amounts 1]
@@ -339,7 +339,7 @@ eval {set name Neo}
eval [list set greeting "Hello, $name"]
-# Therefore, when using "eval", use [list] to build up a desired command
+# Therefore, when using "eval", use [list] to build up a desired command
set command {set name}
lappend command {Archibald Sorbisol}
eval $command
@@ -355,7 +355,7 @@ eval $command ;# There is an error here, because there are too many arguments \
# This mistake can easily occur with the "subst" command.
set replacement {Archibald Sorbisol}
set command {set name $replacement}
-set command [subst $command]
+set command [subst $command]
eval $command ;# The same error as before: too many arguments to "set" in \
{set name Archibald Sorbisol}
@@ -364,12 +364,12 @@ eval $command ;# The same error as before: too many arguments to "set" in \
# command.
set replacement [list {Archibald Sorbisol}]
set command {set name $replacement}
-set command [subst $command]
+set command [subst $command]
eval $command
# It is extremely common to see the "list" command being used to properly
-# format values that are substituted into Tcl script templates. There are
+# format values that are substituted into Tcl script templates. There are
# several examples of this, below.
@@ -422,12 +422,12 @@ proc while {condition script} {
# The "coroutine" command creates a separate call stack, along with a command
# to enter that call stack. The "yield" command suspends execution in that
-# stack.
+# stack.
proc countdown {} {
#send something back to the initial "coroutine" command
yield
- set count 3
+ set count 3
while {$count > 1} {
yield [incr count -1]
}
@@ -435,12 +435,12 @@ proc countdown {} {
}
coroutine countdown1 countdown
coroutine countdown2 countdown
-puts [countdown 1] ;# -> 2
-puts [countdown 2] ;# -> 2
-puts [countdown 1] ;# -> 1
-puts [countdown 1] ;# -> 0
+puts [countdown 1] ;# -> 2
+puts [countdown 2] ;# -> 2
+puts [countdown 1] ;# -> 1
+puts [countdown 1] ;# -> 0
puts [coundown 1] ;# -> invalid command name "countdown1"
-puts [countdown 2] ;# -> 1
+puts [countdown 2] ;# -> 1
```