Description of slparse_assignment

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slparse_assignment

PURPOSE

SLPARSE_ASSIGNMENT Parses an assignment string

SYNOPSIS

function [name, value] = slparse_assignment(str)

DESCRIPTION

SLPARSE_ASSIGNMENT Parses an assignment string

 $ Syntax $
   - [name, value] = slparse_assignment(str)

 $ Arguments $
   - str:          the string representing an assignment
   - name:         the name of the value
   - value:        the value

 $ Description $
   - [name, value] = slparse_assignment(str) parses an assignment string
     and extracts the name and value. The string should be in the form
     of <name> = <value>. For the syntax of assignment, we have following
     rules:
       - spaces are allowed between <name> and = and between = and <value>
       - <name> should be a valid Matlab name, which should be checked
         by isvarname
       - The form of <value> can be either of the following:
           - a numeric scalar (will be converted to double)
           - a matrix as expressed in matlab (will be converted to matrix)
           - a string (will be converted to char string)
           - a string quoted by ' or " (will be de-quoted)

 $ Remarks $
   - The whole string can have multiple =, but only the first one will
     be considered as the assignment mark.

 $ History $
   - Created by Dahua Lin, on Aug 9th, 2006

CROSS-REFERENCE INFORMATION

This function calls:

This function is called by:

• edl_readenvvars EDL_READENVVARS Reads in a file with environment variables

SOURCE CODE

0001 function [name, value] = slparse_assignment(str)
0002 %SLPARSE_ASSIGNMENT Parses an assignment string
0003 %
0004 % $ Syntax $
0005 %   - [name, value] = slparse_assignment(str)
0006 %
0007 % $ Arguments $
0008 %   - str:          the string representing an assignment
0009 %   - name:         the name of the value
0010 %   - value:        the value
0011 %
0012 % $ Description $
0013 %   - [name, value] = slparse_assignment(str) parses an assignment string
0014 %     and extracts the name and value. The string should be in the form
0015 %     of <name> = <value>. For the syntax of assignment, we have following
0016 %     rules:
0017 %       - spaces are allowed between <name> and = and between = and <value>
0018 %       - <name> should be a valid Matlab name, which should be checked
0019 %         by isvarname
0020 %       - The form of <value> can be either of the following:
0021 %           - a numeric scalar (will be converted to double)
0022 %           - a matrix as expressed in matlab (will be converted to matrix)
0023 %           - a string (will be converted to char string)
0024 %           - a string quoted by ' or " (will be de-quoted)
0025 %
0026 % $ Remarks $
0027 %   - The whole string can have multiple =, but only the first one will
0028 %     be considered as the assignment mark.
0029 %
0030 % $ History $
0031 %   - Created by Dahua Lin, on Aug 9th, 2006
0032 %
0033 
0034 %% parse and verify input arguments
0035 
0036 if ~ischar(str)
0037     error('sltoolbox:invalidarg', ...
0038         'The str should be a char string');
0039 end
0040 
0041 str = strtrim(str);
0042 name = [];
0043 value = [];
0044 if isempty(str)
0045     return;
0046 end
0047 
0048 
0049 %% divide parts
0050 
0051 peq = find(str == '=', 1);
0052 if isempty(peq)
0053     error('sltoolbox:parseerror', ...
0054         'Fail to locate the assignment equal mark');
0055 end
0056 
0057 name = strtrim(str(1:peq-1));
0058 value = strtrim(str(peq+1:end));
0059 
0060 %% check name
0061 
0062 if isempty(name) || ~isvarname(name)
0063     error('sltoolbox:parseerror', ...
0064         'The name is invalid for assignment in %s', str);
0065 end
0066 
0067 %% process value
0068 
0069 if isempty(value)
0070     value = [];
0071     return;
0072 end
0073 
0074 trynums = str2num(value);
0075 if ~isempty(trynums)
0076     value = trynums;
0077 elseif length(value) >= 2 && ...
0078         ((value(1) == '''' && value(end) == '''') || (value(1) == '"' && value(end) == '"'))
0079     value = value(2:end-1);
0080     if isempty(value)
0081         value = '';
0082     end
0083 end
0084

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