# Class RegexPattern

OptimaJet.Workflow.Core.CodeActions.RegexPattern

Defines regular-expression patterns for locating and parsing process parameter placeholders in workflow expressions and substitutable text.

Namespace: [OptimaJet.Workflow.Core.CodeActions](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/)

```csharp
public static class RegexPattern
```

## Fields

`public const string Parameter = "(?<FindParameter>(?<MaybeWithBracket>@\\()|(?<WithoutBracket>(?<=[^\\w]|^|\\\\n)@))(?<ParameterName>(?(MaybeWithBracket)[\\w ]+(\\.[\\w ]+)*|\\w+(\\.\\w+)*))((?<MaybeExistsFormat>:(?!\\s*@))|())(?<Format>(?(MaybeExistsFormat)(?(MaybeWithBracket)([^\"'()]|(?<=\\\\)(\\(|\\)|\\\"|'))*|[^\\(\\)\\{\\}\\[\\]\\s\\\"']*)|))(?<EndWithBracketIfExists>(?(MaybeWithBracket)\\)|))"` 

Defines a regular-expression pattern that matches process parameter placeholders with optional format specifiers.

### Remarks

This pattern is built from [RegexPattern.Groups.FindParameter](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/), [RegexPattern.Groups.ParameterName](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/), [RegexPattern.Groups.MaybeExistsFormat](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/), [RegexPattern.Groups.Format](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/), and [RegexPattern.Groups.EndWithBracketIfExists](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/). It matches the placeholder itself without consuming surrounding quotes.

### Example

In `'@document.Employee.Amount:format'` and `"@(document.Employee.Amount:format)"`, the matches are `@document.Employee.Amount:format` and `@(document.Employee.Amount:format)`.

`public const string ParameterAndMaybeQuotes = "(?:((?<MaybeWithSingleQuote>\\')|())|((?<MaybeWithDoubleQuote>\\\")|()))(?<FindParameter>(?<MaybeWithBracket>@\\()|(?<WithoutBracket>(?<=[^\\w]|^|\\\\n)@))(?<ParameterName>(?(MaybeWithBracket)[\\w ]+(\\.[\\w ]+)*|\\w+(\\.\\w+)*))((?<MaybeExistsFormat>:(?!\\s*@))|())(?<Format>(?(MaybeExistsFormat)(?(MaybeWithBracket)([^\"'()]|(?<=\\\\)(\\(|\\)|\\\"|'))*|[^\\(\\)\\{\\}\\[\\]\\s\\\"']*)|))(?<EndWithBracketIfExists>(?(MaybeWithBracket)\\)|))(?<EndWithQuotesIfExists>(?(MaybeWithDoubleQuote)\\\"|(?<EndWithQuotesIfExists>(?(MaybeWithSingleQuote)\\'|))))"` 

Defines a regular-expression pattern that matches a [RegexPattern.Parameter](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern/) placeholder and consumes matching surrounding single or double quotes when present.

### Remarks

This pattern is built from [RegexPattern.Groups.MaybeWithQuotes](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/), [RegexPattern.Parameter](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern/), and [RegexPattern.Groups.EndWithQuotesIfExists](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/). Its named quote groups allow [SubstitutionsProcessor](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/SubstitutionsProcessor/) to distinguish quoted placeholders from unquoted placeholders when producing replacement text.

### Example

In `'@document.Employee.Amount:format'` and `"@(document.Employee.Amount:format)"`, the matches include the surrounding single and double quotes, respectively.

## Nested Types

`public static class RegexPattern.Groups` 

Contains named groups and fragments used to compose placeholder-matching regular-expression patterns.

[View RegexPattern.Groups](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/)

### Remarks

Update group names and related pattern fragments together to keep references in consuming expressions valid.

[Previous IExternalCompiler](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/IExternalCompiler/) [Next RegexPattern.Groups](https://api.workflowengine.io/core/OptimaJet.Workflow.Core.CodeActions/RegexPattern.Groups/)