Entry

TSE: Parser: Syntax: Structure: If: Occurrence: ?: How to create a parser for 0 or 1 occurrences?

Oct 20th, 2003 17:25
Knud van Eeden,

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--- Knud van Eeden --- 25 September 2003 - 01:40 am ------------------

TSE: Parser: Syntax: Structure: If: Occurrence: ?: How to create a 
parser for 0 or 1 occurrences?

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How to possibly parse zero or one occurrence?

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e.g. Suppose you define that a procedure can have parameters or not.

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In words:

A procedure has parameters or not.

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In Backus Naur Form:

[parameter]?

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In Backus Naur Form diagram:

     +--------->---------+
     |                   |
 -->-+->--[parameter]-->-+->--

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In pseudo code:

if 'parameter'
 get 'parameter'
endif

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In pseudo code: in general:

if 'value'
 get 'value'
endif

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As a regular expression: if one character:

 v?

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As a regular expression: if group characters:

 {value}?

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Internet: see also:

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TSE: Parser: Syntax: Structure: Serial: Occurrence: &: And: How create 
parser for serial occurrence?
http://www.faqts.com/knowledge_base/view.phtml/aid/24710/fid/1236

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TSE: Parser:Syntax:Structure:Parallel:Occurrence: |: How create parser 
for 1 or more parallel cases?
http://www.faqts.com/knowledge_base/view.phtml/aid/24705/fid/1236

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TSE: Parser: Syntax:Structure:Repeat: Occurrence: +: How to create 
parser for 1 or more occurrences?
http://www.faqts.com/knowledge_base/view.phtml/aid/24703/fid/1236

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TSE: Parser: Syntax: Structure: While: Occurrence: *: How create 
parser for 0 or more occurrences?
http://www.faqts.com/knowledge_base/view.phtml/aid/24700/fid/1236

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