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This page is for anyone writing text strings in expressions, macros or scripts
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. It also includes information about how to escape special characters.
Using Text Expressions
In PhixFlow, a text expression is made up from a string of characters inside double quotes. Text expressions can also include variable elements so that data from tables or other PhixFlow items can be inserted into the string. The expression must evaluate to a fixed string.
Required output | Example Text Expression | ||
|---|---|---|---|
| Completed | "Completed" | ||
| abc"def | To embed a quote mark:
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The account number ACC46242 failed | Generate a message including the current account number being processed, which is provided by _out.accountNumber:
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This message is finished. |
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Escaping Special Characters
When writing expressions you may need to enter a character that has special meaning. For example, a string could include a double-quote, but in the expression PhixFlow will read this as the end of the string. To tell PhixFlow to ignore a special character, you can use the backslash character.
You must use a backslash to escape any of the special characters listed in the table below.
| Character | Type | Escape string |
|---|---|---|
backspace | Represented As | "\b" |
| Escaped | "\\\\b" | |
| form feed | Represented As | "\f" |
| Escaped | "\\\\f" | |
| tab | Represented As | "\t" |
| Escaped | "\\\\t" | |
| carraige return | Represented As | "\r" |
| Escaped | "\\\\r" | |
| newline | Represented As | "\n" |
| Escaped | "\\\\n" | |
| backslash | Represented As |
|
| Escaped | "\\\\\\\\" | |
| double quote | Represented As | '"' |
| Escaped | '\\\\"' |
Macro: Escaping Invalid Characters
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Example
The following macro escapes
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special characters.
| Code Block | ||
|---|---|---|
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do(
$value = $args[1],
$value = replaceAll( $value , "\b","\\\\b"),
$value = replaceAll( $value , "\f","\\\\f"),
$value = replaceAll( $value , "\t","\\\\t"),
$value = replaceAll( $value , "\r","\\\\r"),
$value = replaceAll( $value , "\n","\\\\n"),
$value = replaceAll( $value , "\\\\","\\\\\\\\"),
$value = replaceAll( $value , '"','\\\\"')
)
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Note: JSON Code can also include characters that cannot be written to the UTF-8 database such as Emojis which are 4 bit characters. This may be solved in the future by migrating the database to UTF-8mb4 but in the meantime, invalid characters can be removed using the following regular expression to do an initial validation on any JSON:
replaceAll(JSON Code,"[^\\p{Space}0-9A-Za-z!:\\\"%&\\[*()\\],-/_\\\\{}\\.]","")
The expression contains a list of expected characters to be found in JSON files. Note how back slashes are used to escape special characters such as [] , . and \
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