--- external help file: PowerShellEditorServices.Commands-help.xml online version: https://github.com/PowerShell/PowerShellEditorServices/tree/master/module/docs/Find-Ast.md schema: 2.0.0 --- # Find-Ast ## SYNOPSIS Find a specific element in an abstract syntax tree (AST). ## SYNTAX ### FilterScript (Default) ```powershell Find-Ast [[-FilterScript] ] [-Ast ] [-Before] [-Family] [-First] [-Last] [-Ancestor] [-IncludeStartingAst] [] ``` ### AtCursor ```powershell Find-Ast [-AtCursor] [] ``` ## DESCRIPTION The Find-Ast function can be used to easily find a specific AST within a script file. All ASTs following the inital starting ast will be searched, including those that are not part of the same tree. The behavior of the search (such as direction and criteria) can be changed with parameters. Additionally, you can find the Ast closest to the cursor with the "AtCursor" switch parameter. ## EXAMPLES ### -------------------------- EXAMPLE 1 -------------------------- ```powershell Find-Ast ``` Returns all asts in the currently open file in the editor. ### -------------------------- EXAMPLE 2 -------------------------- ```powershell Find-Ast -First -IncludeStartingAst ``` Returns the top level ast in the currently open file in the editor. ### -------------------------- EXAMPLE 3 -------------------------- ```powershell Find-Ast { $PSItem -is [FunctionDefinitionAst] } ``` Returns all function definition asts in the ast of file currently open in the editor. ### -------------------------- EXAMPLE 4 -------------------------- ```powershell Find-Ast { $_.Member } ``` Returns all member expressions in the file currently open in the editor. ### -------------------------- EXAMPLE 5 -------------------------- ```powershell Find-Ast { $_.InvocationOperator -eq 'Dot' } | Find-Ast -Family { $_.VariablePath } ``` Returns all variable expressions used in a dot source expression. ### -------------------------- EXAMPLE 6 -------------------------- ```powershell Find-Ast { 'PowerShellVersion' -eq $_ } | Find-Ast -First | Set-ScriptExtent -Text '4.0' -AsString ``` This example sets the required PowerShell version in a module manifest to 4.0. First it finds the AST of the PowerShellVersion manifest field, then finds the first AST directly after it and changes the text to '4.0'. This will not work as is if the field is commented. ### -------------------------- EXAMPLE 7 -------------------------- ```powershell Find-Ast { $_.ArgumentName -eq 'ParameterSetName' -and $_.Argument.Value -eq 'ByPosition' } | Find-Ast -First -Ancestor { $_ -is [System.Management.Automation.Language.ParameterAst] } | ForEach-Object { $_.Name.VariablePath.UserPath } ``` This example gets a list of all parameters that belong to the parameter set 'ByPosition'. First it uses the ArgumentName and Argument properties of NamedAttributeArgumentAst to find the ASTs of arguments to the Parameter attribute that declare the the parameter set 'ByPosition'. It then finds the closest parent ParameterAst and retrieves the name from it. ### -------------------------- EXAMPLE 8 -------------------------- ```powershell $companyName = Find-Ast { $_.Value -eq 'CompanyName' -or (Find-Ast -Ast $_ -First -Before).Value -eq 'CompanyName' } $previousField = $companyName[0] | Find-Ast -First -Before { $_.StringConstantType -eq 'BareWord' } $companyNameComments = $companyName.Extent, $previousField.Extent | Join-ScriptExtent | Get-Token | Where-Object Kind -eq 'Comment' $fullManifestElement = $companyNameComments.Extent, $companyName.Extent | Join-ScriptExtent ``` This example shows off ways you can combine the position functions together to get very specific portions of a script file. The result of this example is a ScriptExtent that includes a manifest field, value, and all comments above it. ## PARAMETERS ### -FilterScript Specifies a ScriptBlock that returns $true if an AST should be returned. Uses $PSItem and $_ like Where-Object. If not specified all ASTs will be returned. ```yaml Type: ScriptBlock Parameter Sets: FilterScript Aliases: Required: False Position: 1 Default value: None Accept pipeline input: False Accept wildcard characters: False ``` ### -Ast Specifies the starting AST. The default is the AST of the current file in PowerShell Editor Services. ```yaml Type: Ast Parameter Sets: FilterScript Aliases: Required: False Position: Named Default value: None Accept pipeline input: True (ByPropertyName, ByValue) Accept wildcard characters: False ``` ### -Before If specified the direction of the search will be reversed. ```yaml Type: SwitchParameter Parameter Sets: FilterScript Aliases: Required: False Position: Named Default value: False Accept pipeline input: False Accept wildcard characters: False ``` ### -Family If specified only children of the starting AST will be searched. If specified with the "Before" parameter then only ancestors will be searched. ```yaml Type: SwitchParameter Parameter Sets: FilterScript Aliases: Required: False Position: Named Default value: False Accept pipeline input: False Accept wildcard characters: False ``` ### -First If specified will return only the first result. This will be the closest AST that matches. ```yaml Type: SwitchParameter Parameter Sets: FilterScript Aliases: Closest, F Required: False Position: Named Default value: False Accept pipeline input: False Accept wildcard characters: False ``` ### -Last If specified will return only the last result. This will be the furthest AST that matches. ```yaml Type: SwitchParameter Parameter Sets: FilterScript Aliases: Furthest Required: False Position: Named Default value: False Accept pipeline input: False Accept wildcard characters: False ``` ### -Ancestor If specified will only search ancestors of the starting AST. This is a convenience parameter that acts the same as the "Family" and "Before" parameters when used together. ```yaml Type: SwitchParameter Parameter Sets: FilterScript Aliases: Parent Required: False Position: Named Default value: False Accept pipeline input: False Accept wildcard characters: False ``` ### -IncludeStartingAst If specified the starting AST will be included if matched. ```yaml Type: SwitchParameter Parameter Sets: FilterScript Aliases: Required: False Position: Named Default value: False Accept pipeline input: False Accept wildcard characters: False ``` ### -AtCursor If specified, this function will return the smallest AST that the cursor is within. ```yaml Type: SwitchParameter Parameter Sets: AtCursor Aliases: Required: False Position: Named Default value: False Accept pipeline input: False Accept wildcard characters: False ``` ### CommonParameters This cmdlet supports the common parameters: -Debug, -ErrorAction, -ErrorVariable, -InformationAction, -InformationVariable, -OutVariable, -OutBuffer, -PipelineVariable, -Verbose, -WarningAction, and -WarningVariable. For more information, see about_CommonParameters (http://go.microsoft.com/fwlink/?LinkID=113216). ## INPUTS ### System.Management.Automation.Language.Ast You can pass ASTs to search to this function. ## OUTPUTS ### System.Management.Automation.Language.Ast ASTs that match the criteria will be returned to the pipeline. ## NOTES ## RELATED LINKS [Get-Token](Get-Token.md) [Set-ScriptExtent](Set-ScriptExtent.md) [ConvertTo-ScriptExtent](ConvertTo-ScriptExtent.md)