private/parser/ClassParameterExpansionParser.psm1
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using module ./EnumParameterExpansionOpTypes.psm1 using module ./ClassSimpleVariableExpression.psm1 using module ./ClassParameterExpansion.psm1 #requires -Version 5 Set-StrictMode -Version Latest class ParameterExpansionParser { [regex]$PREFIX_PATTERN = [regex]'\G(?:[\\$}]|[^\\$}]+)' [string]$str [ParameterExpansion]$expansion ParameterExpansionParser([string]$str) { $this.str = $str $this.expansion = [ParameterExpansion]::new() } [ParameterExpansion]Parse() { [void]$this._Parse(0, 0) return $this.expansion } hidden [int]_Parse([int]$parser_start_index, [int] $nested_levels) { $m = $this.NextMatch($parser_start_index) for (; ; ) { if (($null -eq $m) -or (-not $m.Success)) { if (0 -lt $nested_levels) { # } closing curly brace not found return -1 } break } if ($m.Value.StartsWith('}') -and (0 -lt $nested_levels) ) { # } closing curly brace return ($m.Index + $m.Length) } if ($m.Value.StartsWith('\')) { # escape if(($m.Index + 1) -lt $this.str.Length){ $this.expansion.AddEscapeString(($this.str[$m.Index..($m.Index + 1)] -join "")) $m = $this.NextMatch($m.Index + 2) }else{ $this.expansion.AddEscapeString(($this.str[$m.Index..($m.Index)] -join "")) $m = $this.NextMatch($m.Index + 1) } } elseif ($m.Value.StartsWith('$')) { # variable $next_index = $this.ParseParameterExpansion($m.Index, $nested_levels) $m = $this.NextMatch($next_index) } else { $this.expansion.AddStringLiteral($m.Value) $m = $m.NextMatch() } } return $this.str.Length } hidden [System.Text.RegularExpressions.Match]NextMatch([int]$index) { if ($index -le $this.str.Length) { return $this.PREFIX_PATTERN.Match($this.str, $index) } return $null } hidden [int]ParseParameterExpansion([int]$start_index, [int] $nested_levels) { if ($this.str.IndexOf('${', $start_index, 2) -eq $start_index) { # ${variable} format return $this.ParseCurlyBracesVariableExpansion($start_index, $nested_levels) } $m = ([regex]'\G\$(?<variable_name>[a-zA-Z_][a-zA-Z0-9_]*)').Match($this.str, $start_index) if ($m.Success) { # $variable format $this.expansion.AddSimpleVariable($m.Groups["variable_name"].Value, $m.Value) return ($m.Index + $m.Length) } $this.expansion.AddStringLiteral($this.str[$start_index]) return $start_index + 1 } hidden [int]ParseCurlyBracesVariableExpansion([int]$start_index, [int] $nested_levels) { $m = ([regex]'\G\${(?<variable_name>[a-zA-Z_][a-zA-Z0-9_]*)[:}]').Match($this.str, $start_index) if (-not $m.Success) { Write-Warning -Message "$($this.GetType()): bad substitution: $($this.str.Substring($start_index))" return $this.str.Length } $variable_name = $m.Groups["variable_name"].Value if ($m.Value.EndsWith('}')) { # ${variable} format $this.expansion.AddCurlyBracesVariable([SimpleVariableExpression]::new($variable_name, $m.Value), $null, [ParameterExpansionOpTypes]::BASIC_FORM, $m.Value) return ($m.Index + $m.Length) } if ($m.Value.EndsWith(':')) { # ${variable: format if ("-" -eq $this.str[($m.Index + $m.Length)]) { # ${variable:- format $p = [ParameterExpansionParser]::new($this.str) $next_index = $p._Parse($start_index + $m.Length + 1, $nested_levels + 1) if ($next_index -lt 0) { Write-Warning -Message "$($this.GetType()): bad substitution: $($this.str.Substring($start_index))" return $this.str.Length } $word = $p.expansion $source = $this.str.Substring($start_index, $next_index - $start_index) $param = [SimpleVariableExpression]::new($variable_name, $source); $this.expansion.AddCurlyBracesVariable($param, $word, [ParameterExpansionOpTypes]::PARAMETER_IS_UNSET_OR_NULL, $source) return $next_index } } Write-Warning -Message "$($this.GetType()): bad substitution: $($this.str.Substring($start_index))" return $this.str.Length } } |