Make readme and rework the flags a little

To bring it in line with the xml ones

README.md

@@ -0,0 +1,116 @@
+# Big Chef
+
+A Go-based tool for modifying XML, JSON, and text documents using XPath/JSONPath/Regex expressions and Lua transformations.
+
+## Features
+
+- **Multi-Format Processing**:
+  - XML (XPath)
+  - JSON (JSONPath) 
+  - Text (Regex)
+- **Node Value Modification**: Update text values in XML elements, JSON properties or text matches
+- **Attribute Manipulation**: Modify XML attributes, JSON object keys or regex capture groups
+- **Conditional Logic**: Apply transformations based on document content
+- **Complex Operations**: 
+  - Mathematical calculations
+  - String manipulations
+  - Date conversions
+  - Structural changes
+  - Whole ass Lua environment
+- **Error Handling**: Comprehensive error detection for:
+  - Invalid XML/JSON
+  - Malformed XPath/JSONPath
+  - Lua syntax errors
+
+## Usage Examples
+
+### 1. Basic field modification
+```xml
+<!-- Input -->
+<price>44.95</price>
+
+<!-- Command -->
+chef -xml "//price" "v=v*2" input.xml
+
+<!-- Output -->
+<price>89.9</price>
+```
+
+### 2. Supports glob patterns
+```xml
+chef -xml "//price" "v=v*2" data/**.xml
+```
+
+### 3. Attribute Update
+```xml
+<!-- Input -->
+<item price="10.50"/>
+
+<!-- Command -->
+chef -xml "//item/@price" "v=v*2" input.xml
+
+<!-- Output --> 
+<item price="21"/>
+```
+
+### 3. JSONPath Transformation
+```json
+// Input
+{
+  "products": [
+    {"name": "Widget", "price": 19.99},
+    {"name": "Gadget", "price": 29.99}
+  ]
+}
+
+// Command
+chef -json "$.products[*].price" "v=v*0.75" input.json
+
+// Output
+{
+  "products": [
+    {"name": "Widget", "price": 14.99},
+    {"name": "Gadget", "price": 22.49}
+  ]
+}
+```
+
+### 4. Regex Text Replacement
+Regex works slightly differently, up to 12 match groups are provided as v1..v12 and s1..s12 for numbers and strings respectively.
+A special shorthand "!num" is also provided that simply expands to `(\d*\.?\d+)`.
+```xml
+<!-- Input -->
+<description>Price: $15.00 Special Offer</description>
+
+<!-- Command -->
+chef "Price: $!num Special Offer" "v1 = v1 * 0.92" input.xml
+
+<!-- Output -->
+<description>Price: $13.80 Special Offer</description>
+```
+
+### 5. Conditional Transformation
+```xml
+<!-- Input -->
+<item stock="5" price="10.00"/>
+
+<!-- Command -->
+chef -xml "//item" "if tonumber(v.stock) > 0 then v.price = v.price * 0.8 end" input.xml
+
+<!-- Output -->
+<item stock="5" price="8.00"/>
+```
+
+## Installation
+
+```bash
+go build -o chef main.go
+```
+
+```bash
+# Process XML file
+./chef -xml "//price" "v=v*1.2" input.xml
+
+# Process JSON file 
+./chef -json "$.prices[*]" "v=v*0.9" input.json
+```

go.mod

@@ -3,6 +3,7 @@ module modify
 go 1.24.1
 
 require (
+	github.com/PaesslerAG/jsonpath v0.1.1
 	github.com/antchfx/xmlquery v1.4.4
 	github.com/bmatcuk/doublestar/v4 v4.8.1
 	github.com/yuin/gopher-lua v1.1.1
@@ -10,11 +11,8 @@ require (
 
 require (
 	github.com/PaesslerAG/gval v1.0.0 // indirect
-	github.com/PaesslerAG/jsonpath v0.1.1 // indirect
 	github.com/antchfx/xpath v1.3.3 // indirect
 	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
-	github.com/sergi/go-diff v1.3.1 // indirect
-	github.com/stretchr/testify v1.10.0 // indirect
 	golang.org/x/net v0.33.0 // indirect
 	golang.org/x/text v0.21.0 // indirect
 )

go.sum

@@ -9,21 +9,9 @@ github.com/antchfx/xpath v1.3.3 h1:tmuPQa1Uye0Ym1Zn65vxPgfltWb/Lxu2jeqIGteJSRs=
 github.com/antchfx/xpath v1.3.3/go.mod h1:i54GszH55fYfBmoZXapTHN8T8tkcHfRgLyVwwqzXNcs=
 github.com/bmatcuk/doublestar/v4 v4.8.1 h1:54Bopc5c2cAvhLRAzqOGCYHYyhcDHsFF4wWIR5wKP38=
 github.com/bmatcuk/doublestar/v4 v4.8.1/go.mod h1:xBQ8jztBU6kakFMg+8WGxn0c6z1fTSPVIjEY1Wr7jzc=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da h1:oI5xCqsCo564l8iNU+DwB5epxmsaqB+rhGL0m5jtYqE=
 github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da/go.mod h1:cIg4eruTrX1D+g88fzRXU5OdNfaM+9IcxsU14FzY7Hc=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
-github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
-github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
-github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/sergi/go-diff v1.3.1 h1:xkr+Oxo4BOQKmkn/B9eMK0g5Kg/983T9DqqPHwYqD+8=
-github.com/sergi/go-diff v1.3.1/go.mod h1:aMJSSKb2lpPvRNec0+w3fl7LP9IOFzdc9Pa4NFbPK1I=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.10.0 h1:Xv5erBjTwe/5IxqUQTdXv5kgmIvbHo3QQyRwhJsOfJA=
-github.com/stretchr/testify v1.10.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
 github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
 github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
@@ -92,7 +80,3 @@ golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 golang.org/x/tools v0.13.0/go.mod h1:HvlwmtVNQAhOuCjW7xxvovg8wbNq7LwfXh/k7wXUl58=
 golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
-gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=

main.go

@@ -19,19 +19,12 @@ type GlobalStats struct {
 	FailedFiles        int
 }
 
-type FileMode string
-
-const (
-	ModeRegex FileMode = "regex"
-	ModeXML   FileMode = "xml"
-	ModeJSON  FileMode = "json"
-)
-
 var stats GlobalStats
 var logger *log.Logger
 
 var (
-	fileModeFlag = flag.String("mode", "regex", "Processing mode: regex, xml, json")
+	jsonFlag = flag.Bool("json", false, "Process JSON files")
+	xmlFlag  = flag.Bool("xml", false, "Process XML files")
 )
 
 func init() {
@@ -67,7 +60,7 @@ func main() {
 	args := flag.Args()
 
 	if len(args) < 3 {
-		fmt.Fprintf(os.Stderr, "%s mode requires %d arguments minimum\n", *fileModeFlag, 3)
+		log.Printf("At least %d arguments are required", 3)
 		flag.Usage()
 		return
 	}
@@ -101,20 +94,19 @@ func main() {
 
 	// Create the processor based on mode
 	var proc processor.Processor
-	switch *fileModeFlag {
-	case "regex":
-		proc = &processor.RegexProcessor{}
-		logger.Printf("Starting regex modifier with pattern %q, expression %q on %d files",
+	switch {
+	case *xmlFlag:
+		proc = &processor.XMLProcessor{}
+		logger.Printf("Starting XML modifier with XPath %q, expression %q on %d files",
 			pattern, luaExpr, len(files))
-		// case "xml":
-		// 	proc = &processor.XMLProcessor{}
-		// 	pattern = *xpathFlag
-		// 	logger.Printf("Starting XML modifier with XPath %q, expression %q on %d files",
-		// 		pattern, luaExpr, len(files))
-	case "json":
+	case *jsonFlag:
 		proc = &processor.JSONProcessor{}
 		logger.Printf("Starting JSON modifier with JSONPath %q, expression %q on %d files",
 			pattern, luaExpr, len(files))
+	default:
+		proc = &processor.RegexProcessor{}
+		logger.Printf("Starting regex modifier with pattern %q, expression %q on %d files",
+			pattern, luaExpr, len(files))
 	}
 
 	var wg sync.WaitGroup

processor/json.go

@@ -7,7 +7,6 @@ import (
 	"modify/processor/jsonpath"
 	"os"
 	"path/filepath"
-	"strings"
 
 	lua "github.com/yuin/gopher-lua"
 )
@@ -68,6 +67,7 @@ func (p *JSONProcessor) ProcessContent(content string, pattern string, luaExpr s
 		return content, 0, 0, nil
 	}
 
+	modCount := 0
 	for _, node := range nodes {
 		log.Printf("Processing node at path: %s with value: %v", node.Path, node.Value)
 
@@ -85,10 +85,14 @@ func (p *JSONProcessor) ProcessContent(content string, pattern string, luaExpr s
 		}
 		log.Printf("Converted node value to Lua: %v", node.Value)
 
+		originalScript := luaExpr
+		fullScript := BuildLuaScript(luaExpr)
+		log.Printf("Original script: %q, Full script: %q", originalScript, fullScript)
+
 		// Execute Lua script
-		log.Printf("Executing Lua script: %s", luaExpr)
-		if err := L.DoString(luaExpr); err != nil {
-			return content, len(nodes), 0, fmt.Errorf("error executing Lua %s: %v", luaExpr, err)
+		log.Printf("Executing Lua script: %q", fullScript)
+		if err := L.DoString(fullScript); err != nil {
+			return content, len(nodes), 0, fmt.Errorf("error executing Lua %q: %v", fullScript, err)
 		}
 		log.Println("Lua script executed successfully.")
 
@@ -99,51 +103,29 @@ func (p *JSONProcessor) ProcessContent(content string, pattern string, luaExpr s
 		}
 		log.Printf("Retrieved modified value from Lua: %v", result)
 
+		modified := false
+		modified = L.GetGlobal("modified").String() == "true"
+		if !modified {
+			log.Printf("No changes made to node at path: %s", node.Path)
+			continue
+		}
+
 		// Apply the modification to the JSON data
 		err = p.updateJSONValue(jsonData, node.Path, result)
 		if err != nil {
 			return content, len(nodes), 0, fmt.Errorf("error updating JSON: %v", err)
 		}
 		log.Printf("Updated JSON at path: %s with new value: %v", node.Path, result)
+		modCount++
 	}
 
 	// Convert the modified JSON back to a string with same formatting
 	var jsonBytes []byte
-	if indent, err := detectJsonIndentation(content); err == nil && indent != "" {
-		// Use detected indentation for output formatting
-		jsonBytes, err = json.MarshalIndent(jsonData, "", indent)
-	} else {
-		// Fall back to standard 2-space indent
 	jsonBytes, err = json.MarshalIndent(jsonData, "", "  ")
+	if err != nil {
+		return content, modCount, matchCount, fmt.Errorf("error marshalling JSON: %v", err)
 	}
-
-	// We changed all the nodes trust me bro
-	return string(jsonBytes), len(nodes), len(nodes), nil
-}
-
-// detectJsonIndentation tries to determine the indentation used in the original JSON
-func detectJsonIndentation(content string) (string, error) {
-	lines := strings.Split(content, "\n")
-	if len(lines) < 2 {
-		return "", fmt.Errorf("not enough lines to detect indentation")
-	}
-
-	// Look for the first indented line
-	for i := 1; i < len(lines); i++ {
-		line := lines[i]
-		trimmed := strings.TrimSpace(line)
-		if trimmed == "" {
-			continue
-		}
-
-		// Calculate leading whitespace
-		indent := line[:len(line)-len(trimmed)]
-		if len(indent) > 0 {
-			return indent, nil
-		}
-	}
-
-	return "", fmt.Errorf("no indentation detected")
+	return string(jsonBytes), modCount, matchCount, nil
 }
 
 // / 	Selects from the root node
@@ -165,6 +147,52 @@ func detectJsonIndentation(content string) (string, error) {
 
 // updateJSONValue updates a value in the JSON structure based on its JSONPath
 func (p *JSONProcessor) updateJSONValue(jsonData interface{}, path string, newValue interface{}) error {
+	// Special handling for root node
+	if path == "$" {
+		// For the root node, we'll copy the value to the jsonData reference
+		// This is a special case since we can't directly replace the interface{} variable
+
+		// We need to handle different types of root elements
+		switch rootValue := newValue.(type) {
+		case map[string]interface{}:
+			// For objects, we need to copy over all keys
+			rootMap, ok := jsonData.(map[string]interface{})
+			if !ok {
+				// If the original wasn't a map, completely replace it with the new map
+				// This is handled by the jsonpath.Set function
+				return jsonpath.Set(jsonData, path, newValue)
+			}
+
+			// Clear the original map
+			for k := range rootMap {
+				delete(rootMap, k)
+			}
+
+			// Copy all keys from the new map
+			for k, v := range rootValue {
+				rootMap[k] = v
+			}
+			return nil
+
+		case []interface{}:
+			// For arrays, we need to handle similarly
+			rootArray, ok := jsonData.([]interface{})
+			if !ok {
+				// If the original wasn't an array, use jsonpath.Set
+				return jsonpath.Set(jsonData, path, newValue)
+			}
+
+			// Clear and recreate the array
+			*&rootArray = rootValue
+			return nil
+
+		default:
+			// For other types, use jsonpath.Set
+			return jsonpath.Set(jsonData, path, newValue)
+		}
+	}
+
+	// For non-root paths, use the regular Set method
 	err := jsonpath.Set(jsonData, path, newValue)
 	if err != nil {
 		return fmt.Errorf("failed to update JSON value at path '%s': %w", path, err)

processor/jsonpath/jsonpath.go

@@ -138,10 +138,6 @@ func Set(data interface{}, path string, value interface{}) error {
 		return fmt.Errorf("failed to parse JSONPath %q: %w", path, err)
 	}
 
-	if len(steps) <= 1 {
-		return fmt.Errorf("cannot set root node; the provided path %q is invalid", path)
-	}
-
 	success := false
 	err = setWithPath(data, steps, &success, value, "$", ModifyFirstMode)
 	if err != nil {
@@ -157,10 +153,6 @@ func SetAll(data interface{}, path string, value interface{}) error {
 		return fmt.Errorf("failed to parse JSONPath %q: %w", path, err)
 	}
 
-	if len(steps) <= 1 {
-		return fmt.Errorf("cannot set root node; the provided path %q is invalid", path)
-	}
-
 	success := false
 	err = setWithPath(data, steps, &success, value, "$", ModifyAllMode)
 	if err != nil {
@@ -178,17 +170,20 @@ func setWithPath(node interface{}, steps []JSONStep, success *bool, value interf
 	// Skip root step
 	actualSteps := steps
 	if len(steps) > 0 && steps[0].Type == RootStep {
-		if len(steps) == 1 {
-			return fmt.Errorf("cannot set root node; the provided path %q is invalid", currentPath)
-		}
 		actualSteps = steps[1:]
 	}
 
-	// Process the first step
+	// If we have no steps left, we're setting the root value
 	if len(actualSteps) == 0 {
-		return fmt.Errorf("cannot set root node; no steps provided for path %q", currentPath)
+		// For the root node, we need to handle it differently depending on what's passed in
+		// since we can't directly replace the interface{} variable
+
+		// We'll signal success and let the JSONProcessor handle updating the root
+		*success = true
+		return nil
 	}
 
+	// Process the first step
 	step := actualSteps[0]
 	remainingSteps := actualSteps[1:]
 	isLastStep := len(remainingSteps) == 0

processor/jsonpath/jsonpath_get_set_test.go

@@ -355,14 +355,14 @@ func TestSet(t *testing.T) {
 		}
 	})
 
-	t.Run("setting on root should fail", func(t *testing.T) {
+	t.Run("setting on root should not fail (anymore)", func(t *testing.T) {
 		data := map[string]interface{}{
 			"name": "John",
 		}
 
 		err := Set(data, "$", "Jane")
-		if err == nil {
-			t.Errorf("Set() returned no error, expected error for setting on root")
+		if err != nil {
+			t.Errorf("Set() returned error: %v", err)
 			return
 		}
 

processor/processor.go

@@ -2,7 +2,6 @@ package processor
 
 import (
 	"fmt"
-	"strconv"
 	"strings"
 
 	lua "github.com/yuin/gopher-lua"
@@ -81,6 +80,8 @@ func ToLua(L *lua.LState, data interface{}) (lua.LValue, error) {
 		return lua.LBool(v), nil
 	case float64:
 		return lua.LNumber(v), nil
+	case nil:
+		return lua.LNil, nil
 	default:
 		return nil, fmt.Errorf("unsupported data type: %T", data)
 	}
@@ -89,29 +90,31 @@ func ToLua(L *lua.LState, data interface{}) (lua.LValue, error) {
 // FromLua converts a Lua table to a struct or map recursively
 func FromLua(L *lua.LState, luaValue lua.LValue) (interface{}, error) {
 	switch v := luaValue.(type) {
+	// Well shit...
+	// Tables in lua are both maps and arrays
+	// As arrays they are ordered and as maps, obviously, not
+	// So when we parse them to a go map we fuck up the order for arrays
+	// We have to find a better way....
 	case *lua.LTable:
-		result := make(map[string]interface{})
-		v.ForEach(func(key lua.LValue, value lua.LValue) {
-			result[key.String()], _ = FromLua(L, value)
-		})
-		// This may be a bit wasteful...
-		// Hopefully it won't run often enough to matter
-		isArray := true
-		for key := range result {
-			_, err := strconv.Atoi(key)
+		isArray, err := IsLuaTableArray(L, v)
 		if err != nil {
-				isArray = false
-				break
-			}
+			return nil, err
 		}
 		if isArray {
-			list := make([]interface{}, 0, len(result))
-			for _, value := range result {
-				list = append(list, value)
-			}
-			return list, nil
-		}
+			result := make([]interface{}, 0)
+			v.ForEach(func(key lua.LValue, value lua.LValue) {
+				converted, _ := FromLua(L, value)
+				result = append(result, converted)
+			})
 			return result, nil
+		} else {
+			result := make(map[string]interface{})
+			v.ForEach(func(key lua.LValue, value lua.LValue) {
+				converted, _ := FromLua(L, value)
+				result[key.String()] = converted
+			})
+			return result, nil
+		}
 	case lua.LString:
 		return string(v), nil
 	case lua.LBool:
@@ -123,13 +126,34 @@ func FromLua(L *lua.LState, luaValue lua.LValue) (interface{}, error) {
 	}
 }
 
+func IsLuaTableArray(L *lua.LState, v *lua.LTable) (bool, error) {
+	L.SetGlobal("table_to_check", v)
+
+	// Use our predefined helper function from InitLuaHelpers
+	err := L.DoString(`is_array = isArray(table_to_check)`)
+	if err != nil {
+		return false, fmt.Errorf("error determining if table is array: %w", err)
+	}
+
+	// Check the result of our Lua function
+	isArray := L.GetGlobal("is_array")
+	// LVIsFalse returns true if a given LValue is a nil or false otherwise false.
+	if !lua.LVIsFalse(isArray) {
+		return true, nil
+	}
+	return false, nil
+}
+
 // InitLuaHelpers initializes common Lua helper functions
 func InitLuaHelpers(L *lua.LState) error {
 	helperScript := `
 -- Custom Lua helpers for math operations
 function min(a, b) return math.min(a, b) end
 function max(a, b) return math.max(a, b) end
-function round(x) return math.floor(x + 0.5) end
+function round(x, n)
+	if n == nil then n = 0 end
+	return math.floor(x * 10^n + 0.5) / 10^n
+end
 function floor(x) return math.floor(x) end
 function ceil(x) return math.ceil(x) end
 function upper(s) return string.upper(s) end
@@ -149,6 +173,22 @@ end
 function is_number(str)
     return tonumber(str) ~= nil
 end
+
+function isArray(t)
+    if type(t) ~= "table" then return false end
+    local max = 0
+    local count = 0
+    for k, _ in pairs(t) do
+        if type(k) ~= "number" or k < 1 or math.floor(k) ~= k then
+            return false
+        end
+        max = math.max(max, k)
+        count = count + 1
+    end
+    return max == count
+end
+
+modified = false
 `
 	if err := L.DoString(helperScript); err != nil {
 		return fmt.Errorf("error loading helper functions: %v", err)
@@ -167,8 +207,7 @@ func LimitString(s string, maxLen int) string {
 	return s[:maxLen-3] + "..."
 }
 
-// BuildLuaScript prepares a Lua expression from shorthand notation
-func BuildLuaScript(luaExpr string) string {
+func PrependLuaAssignment(luaExpr string) string {
 	// Auto-prepend v1 for expressions starting with operators
 	if strings.HasPrefix(luaExpr, "*") ||
 		strings.HasPrefix(luaExpr, "/") ||
@@ -186,10 +225,30 @@ func BuildLuaScript(luaExpr string) string {
 	if !strings.Contains(luaExpr, "=") {
 		luaExpr = "v1 = " + luaExpr
 	}
-
 	return luaExpr
 }
 
+// BuildLuaScript prepares a Lua expression from shorthand notation
+func BuildLuaScript(luaExpr string) string {
+	luaExpr = PrependLuaAssignment(luaExpr)
+
+	// This allows the user to specify whether or not they modified a value
+	// If they do nothing we assume they did modify (no return at all)
+	// If they return before our return then they themselves specify what they did
+	// If nothing is returned lua assumes nil
+	// So we can say our value was modified if the return value is either nil or true
+	// If the return value is false then the user wants to keep the original
+	fullScript := fmt.Sprintf(`
+		function run()
+			%s
+		end
+		local res = run()
+		modified = res == nil or res
+	`, luaExpr)
+
+	return fullScript
+}
+
 // Max returns the maximum of two integers
 func Max(a, b int) int {
 	if a > b {

processor/regex_test.go

@@ -35,10 +35,11 @@ func TestBuildLuaScript(t *testing.T) {
 		{"v1 * 2", "v1 = v1 * 2"},
 		{"v1 * v2", "v1 = v1 * v2"},
 		{"v1 / v2", "v1 = v1 / v2"},
+		{"12", "v1 = 12"},
 	}
 
 	for _, c := range cases {
-		result := BuildLuaScript(c.input)
+		result := PrependLuaAssignment(c.input)
 		if result != c.expected {
 			t.Errorf("BuildLuaScript(%q): expected %q, got %q", c.input, c.expected, result)
 		}

processor/xpath/xpath.go

@@ -0,0 +1,98 @@
+package xpath
+
+import "errors"
+
+// XPathStep represents a single step in an XPath expression
+type XPathStep struct {
+	Type      StepType
+	Name      string
+	Predicate *Predicate
+}
+
+// StepType defines the type of XPath step
+type StepType int
+
+const (
+	// RootStep represents the root step (/)
+	RootStep StepType = iota
+	// ChildStep represents a child element step (element)
+	ChildStep
+	// RecursiveDescentStep represents a recursive descent step (//)
+	RecursiveDescentStep
+	// WildcardStep represents a wildcard step (*)
+	WildcardStep
+	// PredicateStep represents a predicate condition step ([...])
+	PredicateStep
+)
+
+// PredicateType defines the type of XPath predicate
+type PredicateType int
+
+const (
+	// IndexPredicate represents an index predicate [n]
+	IndexPredicate PredicateType = iota
+	// LastPredicate represents a last() function predicate
+	LastPredicate
+	// LastMinusPredicate represents a last()-n predicate
+	LastMinusPredicate
+	// PositionPredicate represents position()-based predicates
+	PositionPredicate
+	// AttributeExistsPredicate represents [@attr] predicate
+	AttributeExistsPredicate
+	// AttributeEqualsPredicate represents [@attr='value'] predicate
+	AttributeEqualsPredicate
+	// ComparisonPredicate represents element comparison predicates
+	ComparisonPredicate
+)
+
+// Predicate represents a condition in XPath
+type Predicate struct {
+	Type       PredicateType
+	Index      int
+	Offset     int
+	Attribute  string
+	Value      string
+	Expression string
+}
+
+// XMLNode represents a node in the result set with its value and path
+type XMLNode struct {
+	Value interface{}
+	Path  string
+}
+
+// ParseXPath parses an XPath expression into a series of steps
+func ParseXPath(path string) ([]XPathStep, error) {
+	if path == "" {
+		return nil, errors.New("empty path")
+	}
+
+	// This is just a placeholder implementation for the tests
+	// The actual implementation would parse the XPath expression
+	return nil, errors.New("not implemented")
+}
+
+// Get retrieves nodes from XML data using an XPath expression
+func Get(data interface{}, path string) ([]XMLNode, error) {
+	if data == "" {
+		return nil, errors.New("empty XML data")
+	}
+
+	// This is just a placeholder implementation for the tests
+	// The actual implementation would evaluate the XPath against the XML
+	return nil, errors.New("not implemented")
+}
+
+// Set updates a node in the XML data using an XPath expression
+func Set(xmlData string, path string, value interface{}) (string, error) {
+	// This is just a placeholder implementation for the tests
+	// The actual implementation would modify the XML based on the XPath
+	return "", errors.New("not implemented")
+}
+
+// SetAll updates all nodes matching an XPath expression in the XML data
+func SetAll(xmlData string, path string, value interface{}) (string, error) {
+	// This is just a placeholder implementation for the tests
+	// The actual implementation would modify all matching nodes
+	return "", errors.New("not implemented")
+}

processor/xpath/xpath_test.go

@@ -0,0 +1,545 @@
+package xpath
+
+import (
+	"reflect"
+	"testing"
+)
+
+// XML test data as a string for our tests
+var testXML = `
+<store>
+  <book category="fiction">
+    <title lang="en">The Fellowship of the Ring</title>
+    <author>J.R.R. Tolkien</author>
+    <year>1954</year>
+    <price>22.99</price>
+  </book>
+  <book category="fiction">
+    <title lang="en">The Two Towers</title>
+    <author>J.R.R. Tolkien</author>
+    <year>1954</year>
+    <price>23.45</price>
+  </book>
+  <book category="technical">
+    <title lang="en">Learning XML</title>
+    <author>Erik T. Ray</author>
+    <year>2003</year>
+    <price>39.95</price>
+  </book>
+  <bicycle>
+    <color>red</color>
+    <price>199.95</price>
+  </bicycle>
+</store>
+`
+
+func TestParser(t *testing.T) {
+	tests := []struct {
+		path    string
+		steps   []XPathStep
+		wantErr bool
+	}{
+		{
+			path: "/store/bicycle/color",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: ChildStep, Name: "store"},
+				{Type: ChildStep, Name: "bicycle"},
+				{Type: ChildStep, Name: "color"},
+			},
+		},
+		{
+			path: "//price",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: RecursiveDescentStep, Name: "price"},
+			},
+		},
+		{
+			path: "/store/book/*",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: ChildStep, Name: "store"},
+				{Type: ChildStep, Name: "book"},
+				{Type: WildcardStep},
+			},
+		},
+		{
+			path: "/store/book[1]/title",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: ChildStep, Name: "store"},
+				{Type: ChildStep, Name: "book"},
+				{Type: PredicateStep, Predicate: &Predicate{Type: IndexPredicate, Index: 1}},
+				{Type: ChildStep, Name: "title"},
+			},
+		},
+		{
+			path: "//title[@lang]",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: RecursiveDescentStep, Name: "title"},
+				{Type: PredicateStep, Predicate: &Predicate{Type: AttributeExistsPredicate, Attribute: "lang"}},
+			},
+		},
+		{
+			path: "//title[@lang='en']",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: RecursiveDescentStep, Name: "title"},
+				{Type: PredicateStep, Predicate: &Predicate{
+					Type:      AttributeEqualsPredicate,
+					Attribute: "lang",
+					Value:     "en",
+				}},
+			},
+		},
+		{
+			path: "/store/book[price>35.00]/title",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: ChildStep, Name: "store"},
+				{Type: ChildStep, Name: "book"},
+				{Type: PredicateStep, Predicate: &Predicate{
+					Type:       ComparisonPredicate,
+					Expression: "price>35.00",
+				}},
+				{Type: ChildStep, Name: "title"},
+			},
+		},
+		{
+			path: "/store/book[last()]",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: ChildStep, Name: "store"},
+				{Type: ChildStep, Name: "book"},
+				{Type: PredicateStep, Predicate: &Predicate{Type: LastPredicate}},
+			},
+		},
+		{
+			path: "/store/book[last()-1]",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: ChildStep, Name: "store"},
+				{Type: ChildStep, Name: "book"},
+				{Type: PredicateStep, Predicate: &Predicate{
+					Type:   LastMinusPredicate,
+					Offset: 1,
+				}},
+			},
+		},
+		{
+			path: "/store/book[position()<3]",
+			steps: []XPathStep{
+				{Type: RootStep},
+				{Type: ChildStep, Name: "store"},
+				{Type: ChildStep, Name: "book"},
+				{Type: PredicateStep, Predicate: &Predicate{
+					Type:       PositionPredicate,
+					Expression: "position()<3",
+				}},
+			},
+		},
+		{
+			path:    "invalid/path",
+			wantErr: true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.path, func(t *testing.T) {
+			steps, err := ParseXPath(tt.path)
+			if (err != nil) != tt.wantErr {
+				t.Fatalf("ParseXPath() error = %v, wantErr %v", err, tt.wantErr)
+			}
+			if !tt.wantErr && !reflect.DeepEqual(steps, tt.steps) {
+				t.Errorf("ParseXPath() steps = %+v, want %+v", steps, tt.steps)
+			}
+		})
+	}
+}
+
+func TestEvaluator(t *testing.T) {
+	tests := []struct {
+		name     string
+		path     string
+		expected []XMLNode
+		error    bool
+	}{
+		{
+			name: "simple_element_access",
+			path: "/store/bicycle/color",
+			expected: []XMLNode{
+				{Value: "red", Path: "/store/bicycle/color"},
+			},
+		},
+		{
+			name: "recursive_element_access",
+			path: "//price",
+			expected: []XMLNode{
+				{Value: "22.99", Path: "/store/book[1]/price"},
+				{Value: "23.45", Path: "/store/book[2]/price"},
+				{Value: "39.95", Path: "/store/book[3]/price"},
+				{Value: "199.95", Path: "/store/bicycle/price"},
+			},
+		},
+		{
+			name: "wildcard_element_access",
+			path: "/store/book[1]/*",
+			expected: []XMLNode{
+				{Value: "The Fellowship of the Ring", Path: "/store/book[1]/title"},
+				{Value: "J.R.R. Tolkien", Path: "/store/book[1]/author"},
+				{Value: "1954", Path: "/store/book[1]/year"},
+				{Value: "22.99", Path: "/store/book[1]/price"},
+			},
+		},
+		{
+			name: "indexed_element_access",
+			path: "/store/book[1]/title",
+			expected: []XMLNode{
+				{Value: "The Fellowship of the Ring", Path: "/store/book[1]/title"},
+			},
+		},
+		{
+			name: "attribute_exists_predicate",
+			path: "//title[@lang]",
+			expected: []XMLNode{
+				{Value: "The Fellowship of the Ring", Path: "/store/book[1]/title"},
+				{Value: "The Two Towers", Path: "/store/book[2]/title"},
+				{Value: "Learning XML", Path: "/store/book[3]/title"},
+			},
+		},
+		{
+			name: "attribute_equals_predicate",
+			path: "//title[@lang='en']",
+			expected: []XMLNode{
+				{Value: "The Fellowship of the Ring", Path: "/store/book[1]/title"},
+				{Value: "The Two Towers", Path: "/store/book[2]/title"},
+				{Value: "Learning XML", Path: "/store/book[3]/title"},
+			},
+		},
+		{
+			name: "value_comparison_predicate",
+			path: "/store/book[price>35.00]/title",
+			expected: []XMLNode{
+				{Value: "Learning XML", Path: "/store/book[3]/title"},
+			},
+		},
+		{
+			name: "last_predicate",
+			path: "/store/book[last()]/title",
+			expected: []XMLNode{
+				{Value: "Learning XML", Path: "/store/book[3]/title"},
+			},
+		},
+		{
+			name: "last_minus_predicate",
+			path: "/store/book[last()-1]/title",
+			expected: []XMLNode{
+				{Value: "The Two Towers", Path: "/store/book[2]/title"},
+			},
+		},
+		{
+			name: "position_predicate",
+			path: "/store/book[position()<3]/title",
+			expected: []XMLNode{
+				{Value: "The Fellowship of the Ring", Path: "/store/book[1]/title"},
+				{Value: "The Two Towers", Path: "/store/book[2]/title"},
+			},
+		},
+		{
+			name:     "all_elements",
+			path:     "//*",
+			expected: []XMLNode{
+				// For brevity, we'll just check the count, not all values
+			},
+		},
+		{
+			name:     "invalid_index",
+			path:     "/store/book[10]/title",
+			expected: []XMLNode{},
+			error:    true,
+		},
+		{
+			name:     "nonexistent_element",
+			path:     "/store/nonexistent",
+			expected: []XMLNode{},
+			error:    true,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := Get(testXML, tt.path)
+			if err != nil {
+				if !tt.error {
+					t.Errorf("Get() returned error: %v", err)
+				}
+				return
+			}
+
+			// Special handling for the "//*" test case
+			if tt.path == "//*" {
+				// Just check that we got multiple elements, not the specific count
+				if len(result) < 10 { // We expect at least 10 elements
+					t.Errorf("Expected multiple elements for '//*', got %d", len(result))
+				}
+				return
+			}
+
+			if len(result) != len(tt.expected) {
+				t.Errorf("Expected %d items, got %d", len(tt.expected), len(result))
+				return
+			}
+
+			// Validate both values and paths
+			for i, e := range tt.expected {
+				if i < len(result) {
+					if !reflect.DeepEqual(result[i].Value, e.Value) {
+						t.Errorf("Value at [%d]: got %v, expected %v", i, result[i].Value, e.Value)
+					}
+					if result[i].Path != e.Path {
+						t.Errorf("Path at [%d]: got %s, expected %s", i, result[i].Path, e.Path)
+					}
+				}
+			}
+		})
+	}
+}
+
+func TestEdgeCases(t *testing.T) {
+	t.Run("empty_data", func(t *testing.T) {
+		result, err := Get("", "/store/book")
+		if err == nil {
+			t.Errorf("Expected error for empty data")
+			return
+		}
+		if len(result) > 0 {
+			t.Errorf("Expected empty result, got %v", result)
+		}
+	})
+
+	t.Run("empty_path", func(t *testing.T) {
+		_, err := ParseXPath("")
+		if err == nil {
+			t.Error("Expected error for empty path")
+		}
+	})
+
+	t.Run("invalid_xml", func(t *testing.T) {
+		_, err := Get("<invalid>xml", "/store")
+		if err == nil {
+			t.Error("Expected error for invalid XML")
+		}
+	})
+
+	t.Run("current_node", func(t *testing.T) {
+		result, err := Get(testXML, "/store/book[1]/.")
+		if err != nil {
+			t.Errorf("Get() returned error: %v", err)
+			return
+		}
+		if len(result) != 1 {
+			t.Errorf("Expected 1 result, got %d", len(result))
+		}
+	})
+
+	t.Run("attributes", func(t *testing.T) {
+		result, err := Get(testXML, "/store/book[1]/title/@lang")
+		if err != nil {
+			t.Errorf("Get() returned error: %v", err)
+			return
+		}
+		if len(result) != 1 || result[0].Value != "en" {
+			t.Errorf("Expected 'en', got %v", result)
+		}
+	})
+}
+
+func TestGetWithPaths(t *testing.T) {
+	tests := []struct {
+		name     string
+		path     string
+		expected []XMLNode
+	}{
+		{
+			name: "simple_element_access",
+			path: "/store/bicycle/color",
+			expected: []XMLNode{
+				{Value: "red", Path: "/store/bicycle/color"},
+			},
+		},
+		{
+			name: "indexed_element_access",
+			path: "/store/book[1]/title",
+			expected: []XMLNode{
+				{Value: "The Fellowship of the Ring", Path: "/store/book[1]/title"},
+			},
+		},
+		{
+			name: "recursive_element_access",
+			path: "//price",
+			expected: []XMLNode{
+				{Value: "22.99", Path: "/store/book[1]/price"},
+				{Value: "23.45", Path: "/store/book[2]/price"},
+				{Value: "39.95", Path: "/store/book[3]/price"},
+				{Value: "199.95", Path: "/store/bicycle/price"},
+			},
+		},
+		{
+			name: "attribute_access",
+			path: "/store/book[1]/title/@lang",
+			expected: []XMLNode{
+				{Value: "en", Path: "/store/book[1]/title/@lang"},
+			},
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			result, err := Get(testXML, tt.path)
+			if err != nil {
+				t.Errorf("Get() returned error: %v", err)
+				return
+			}
+
+			// Check if lengths match
+			if len(result) != len(tt.expected) {
+				t.Errorf("Get() returned %d items, expected %d", len(result), len(tt.expected))
+				return
+			}
+
+			// For each expected item, find its match in the results and verify both value and path
+			for _, expected := range tt.expected {
+				found := false
+				for _, r := range result {
+					// First verify the value matches
+					if reflect.DeepEqual(r.Value, expected.Value) {
+						found = true
+						// Then verify the path matches
+						if r.Path != expected.Path {
+							t.Errorf("Path mismatch for value %v: got %s, expected %s", r.Value, r.Path, expected.Path)
+						}
+						break
+					}
+				}
+				if !found {
+					t.Errorf("Expected node with value %v and path %s not found in results", expected.Value, expected.Path)
+				}
+			}
+		})
+	}
+}
+
+func TestSet(t *testing.T) {
+	t.Run("simple element", func(t *testing.T) {
+		xmlData := `<root><name>John</name></root>`
+		newXML, err := Set(xmlData, "/root/name", "Jane")
+		if err != nil {
+			t.Errorf("Set() returned error: %v", err)
+			return
+		}
+
+		// Verify the change
+		result, err := Get(newXML, "/root/name")
+		if err != nil {
+			t.Errorf("Get() returned error: %v", err)
+			return
+		}
+		if len(result) != 1 || result[0].Value != "Jane" {
+			t.Errorf("Set() failed: expected name to be 'Jane', got %v", result)
+		}
+	})
+
+	t.Run("attribute", func(t *testing.T) {
+		xmlData := `<root><element id="123"></element></root>`
+		newXML, err := Set(xmlData, "/root/element/@id", "456")
+		if err != nil {
+			t.Errorf("Set() returned error: %v", err)
+			return
+		}
+
+		// Verify the change
+		result, err := Get(newXML, "/root/element/@id")
+		if err != nil {
+			t.Errorf("Get() returned error: %v", err)
+			return
+		}
+		if len(result) != 1 || result[0].Value != "456" {
+			t.Errorf("Set() failed: expected id to be '456', got %v", result)
+		}
+	})
+
+	t.Run("indexed element", func(t *testing.T) {
+		xmlData := `<root><items><item>first</item><item>second</item></items></root>`
+		newXML, err := Set(xmlData, "/root/items/item[1]", "changed")
+		if err != nil {
+			t.Errorf("Set() returned error: %v", err)
+			return
+		}
+
+		// Verify the change
+		result, err := Get(newXML, "/root/items/item[1]")
+		if err != nil {
+			t.Errorf("Get() returned error: %v", err)
+			return
+		}
+		if len(result) != 1 || result[0].Value != "changed" {
+			t.Errorf("Set() failed: expected item to be 'changed', got %v", result)
+		}
+	})
+}
+
+func TestSetAll(t *testing.T) {
+	t.Run("multiple elements", func(t *testing.T) {
+		xmlData := `<root><items><item>first</item><item>second</item></items></root>`
+		newXML, err := SetAll(xmlData, "//item", "changed")
+		if err != nil {
+			t.Errorf("SetAll() returned error: %v", err)
+			return
+		}
+
+		// Verify all items are changed
+		result, err := Get(newXML, "//item")
+		if err != nil {
+			t.Errorf("Get() returned error: %v", err)
+			return
+		}
+		if len(result) != 2 {
+			t.Errorf("Expected 2 results, got %d", len(result))
+			return
+		}
+
+		for i, node := range result {
+			if node.Value != "changed" {
+				t.Errorf("Item %d not changed, got %v", i+1, node.Value)
+			}
+		}
+	})
+
+	t.Run("attributes", func(t *testing.T) {
+		xmlData := `<root><item id="1"/><item id="2"/></root>`
+		newXML, err := SetAll(xmlData, "//item/@id", "new")
+		if err != nil {
+			t.Errorf("SetAll() returned error: %v", err)
+			return
+		}
+
+		// Verify all attributes are changed
+		result, err := Get(newXML, "//item/@id")
+		if err != nil {
+			t.Errorf("Get() returned error: %v", err)
+			return
+		}
+		if len(result) != 2 {
+			t.Errorf("Expected 2 results, got %d", len(result))
+			return
+		}
+
+		for i, node := range result {
+			if node.Value != "new" {
+				t.Errorf("Attribute %d not changed, got %v", i+1, node.Value)
+			}
+		}
+	})
+}

release.sh

@@ -16,7 +16,7 @@ fi
 echo "Tag: $TAG"
 
 echo "Building the thing..."
-go build -o BigChef.exe .
+go build -o chef.exe .
 
 echo "Creating a release..."
 TOKEN="$GITEA_API_KEY"
@@ -43,6 +43,6 @@ echo "Release ID: $RELEASE_ID"
 echo "Uploading the things..."
 curl -X POST \
   -H "Authorization: token $TOKEN" \
-  -F "attachment=@BigChef.exe" \
-  "$GITEA/api/v1/repos/$REPO/releases/${RELEASE_ID}/assets?name=BigChef.exe"
-rm BigChef.exe
+  -F "attachment=@chef.exe" \
+  "$GITEA/api/v1/repos/$REPO/releases/${RELEASE_ID}/assets?name=chef.exe"
+rm chef.exe