Statements and Control Structures

Basic Syntax: Statements and Control Structures

IV. Statements

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1. Statement Blocks Represented by {}. Generally used for flow control statements.

2. Statement Groups (Subcommand Capture) Subcommands are represented in parentheses; subcommands do not create new processes and do not isolate variable scopes. echo (len [5,6])

3. Statements Separated by ; or enter.

• Newline: ; or enter.

• Continuation: Use \ + newline to write across lines.

  1let long_expr = 3 \
  2             + 5  # equivalent to "3 + 5"
  3
  4let long_str = "Hello
  5                World"  # equivalent to "Hello\n World"

  Note: Content within quotes does not require a continuation character.

4. Comments Comments start with #.

V. Control Structures

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Conditional Statements

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If Condition

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Supports nesting:

if cond1 { ... } else if cond2 { ... } else { ... }

Does not use the then keyword; code blocks are wrapped in {}.

1if True {1} else {if False {2} else {3}}
2
3if x > 10 {
4    print("Large")
5} else if x == 10 {
6    print("Equal")
7} else {
8    print("Small")
9}

Match Statement

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Replaces the switch statement in bash. Supports matching multiple options in one branch, separated by ; or newlines. Supports regex matching. Supports literal direct matching, which will not be interpreted as variables.

1let fruit = "apple"
2match fruit {
3  pea,cherry => print "is my favor"
4  "*pple" => print "is my love"
5  r'\d' => print "is number"
6    _  => print "is others"
7}

Loop Statements

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Repeat Loop

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1repeat 10 {a += 1}   # outputs [1,2...10]

For Loop

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1for i in 0..5 {    # outputs 0,1,2,3,4
2    print(i)
3}
4
5for i in [1,5,8] { print i }
6
7for i in *.md {      # supports * expansion
8  Fs.cp i /tmp/
9}

Supports * expansion.

While Loop

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1let count = 0
2while count < 3 {
3    print(count)
4    count = count + 1
5}

Loop Loop

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1let count = 0
2let result = loop {             # statements can also be used as expressions
3  print(count)
4  count = count + 1
5  if count > 3 {
6      break count
7  }
8}
9print result

Statement Expressions

#

• Control statements can also be used as expressions:

  1let a = if b>0 {5} else {-5}

• Conditional Expression

  1a = c>0 ? t : f

Supports nesting. [1] https://www.lix.polytechnique.fr/~liberti/public/computing/prog/c/C/SYNTAX/statements.html [2] https://en.wikipedia.org/wiki/Block_(programming) [3] https://mc-stan.org/docs/2_19/reference-manual/statement-blocks-and-local-variable-declarations.html [4] https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/block [5] https://www.alooba.com/skills/concepts/programming/programming-concepts/control-structures/ [6] https://www.unison-lang.org/docs/language-reference/blocks-and-statements/ [7] https://documentation.sas.com/doc/hi/pgmsascdc/v_042/grstatug/p11cgiqvwqcmchn14bgmjnx4d7h2.htm [8] https://www.ibm.com/docs/en/i/7.5.0?topic=statements-block [9] https://docs.oracle.com/javase/specs/jls/se7/html/jls-14.html [10] https://www.scribd.com/document/842472631/Basic-Syntax-and-Control-Structures [11] https://www.geeksforgeeks.org/dsa/control-structures-in-programming-languages/ [12] https://www.php.net/manual/en/language.control-structures.php [13] https://docs.getdbt.com/reference/dbt-jinja-functions/statement-blocks [14] https://en.wikibooks.org/wiki/BASIC_Programming/Beginning_BASIC/Control_Structures/IF...THEN...ELSEIF...ELSE [15] https://www.reddit.com/r/learnprogramming/comments/y4jmc0/what_are_control_flow_control_statements_and/ [16] https://www.alice.org/resources/lessons/control-structures-overview/ [17] https://help.deltek.com/product/ajera/8/content/About_statement_groups.htm [18] https://userapps.support.sap.com/sap/support/knowledge/en/2084915 [19] https://medium.com/@shirhabeel_awan/control-structures-loops-conditional-statements-and-functions-bf10231519b3 [20] https://metana.io/blog/javascript-control-structures/ [21] https://www.restaurant-hospitality.com/new-restaurants/gina-luari-launches-the-statement-group-in-connecticut [22] https://us-kb.sage.com/portal/app/portlets/results/view2.jsp?k2dockey=222924150017120 [23] https://community.qualtrics.com/survey-platform-54/how-do-i-make-statement-group-titles-show-in-the-matrix-question-31700?postid=108288 [24] https://www.w3schools.com/sql/sql_groupby.asp [25] https://www.alooba.com/skills/concepts/csharp-243/syntax-and-structure/ [26] https://www.thestatementgroup.com/ [27] https://docs.particle.io/reference/device-os/api/language-syntax/control-structures/ [28] https://www.cs.fsu.edu/~myers/c++/notes/control1.html [29] https://www.kdnuggets.com/python-basics-syntax-data-types-and-control-structures [30] https://docs.scala-lang.org/scala3/book/control-structures.html [31] https://dictionary.cambridge.org/us/dictionary/english/comment [32] https://www.vocabulary.com/dictionary/comment [33] https://en.wikipedia.org/wiki/Comment_(computer_programming) [34] https://support.google.com/youtube/answer/6000976?hl=en [35] https://www.dictionary.com/browse/comment [36] https://www.merriam-webster.com/dictionary/comment [37] https://socialbee.com/glossary/comment/ [38] https://www.thesaurus.com/browse/comment