Add variable support

Author: Aerijo

lib/snippet-expansion.js

@@ -14,22 +14,27 @@ module.exports = class SnippetExpansion {
     this.selections = [this.cursor.selection]
 
     const startPosition = this.cursor.selection.getBufferRange().start
-    let {body, tabStopList} = this.snippet
-    let tabStops = tabStopList.toArray()
+    let {body, tabStopList} = this.snippet.toString()
+
+    this.tabStopList = tabStopList
+
+    let tabStops = this.tabStopList.toArray()
 
     let indent = this.editor.lineTextForBufferRow(startPosition.row).match(/^\s*/)[0]
     if (this.snippet.lineCount > 1 && indent) {
       // Add proper leading indentation to the snippet
       body = body.replace(/\n/g, `\n${indent}`)
 
+      // TODO: Remove concept of "body"; build on the fly each time to resolve variables and their transformations
+
       tabStops = tabStops.map(tabStop => tabStop.copyWithIndent(indent))
     }
 
     this.editor.transact(() => {
       this.ignoringBufferChanges(() => {
         this.editor.transact(() => {
           const newRange = this.cursor.selection.insertText(body, {autoIndent: false})
-          if (this.snippet.tabStopList.length > 0) {
+          if (this.tabStopList.length > 0) {
             this.subscriptions.add(this.cursor.onDidChangePosition(event => this.cursorMoved(event)))
             this.subscriptions.add(this.cursor.onDidDestroy(() => this.cursorDestroyed()))
             this.placeTabStopMarkers(startPosition, tabStops)
@@ -152,7 +157,7 @@ module.exports = class SnippetExpansion {
     } else {
       // The user has tabbed past the last tab stop. If the last tab stop is a
       // $0, we shouldn't move the cursor any further.
-      if (this.snippet.tabStopList.hasEndStop) {
+      if (this.tabStopList.hasEndStop) { foo
         this.destroy()
         return false
       } else {

lib/snippet.js

@@ -1,56 +1,81 @@
 const {Range} = require('atom')
 const TabStopList = require('./tab-stop-list')
 
+
+/*
+
+1. Snippet stores the parsed snippet template
+
+2. Template variables are resolved on demand
+
+3. Followed by insertion
+
+*/
+
 module.exports = class Snippet {
-  constructor({name, prefix, bodyText, description, descriptionMoreURL, rightLabelHTML, leftLabel, leftLabelHTML, bodyTree}) {
+  constructor({name, prefix, description, descriptionMoreURL, rightLabelHTML, leftLabel, leftLabelHTML, bodyTree, variableResolver}) {
     this.name = name
     this.prefix = prefix
-    this.bodyText = bodyText
     this.description = description
     this.descriptionMoreURL = descriptionMoreURL
     this.rightLabelHTML = rightLabelHTML
     this.leftLabel = leftLabel
     this.leftLabelHTML = leftLabelHTML
-    this.tabStopList = new TabStopList(this)
-    this.body = this.extractTabStops(bodyTree)
+    this.bodyTree = bodyTree
+    this.variableResolver = variableResolver
   }
 
-  extractTabStops (bodyTree) {
+  toString () {
+    const tabStopList = new TabStopList(this)
     const bodyText = []
     let row = 0
     let column = 0
 
     // recursive helper function; mutates vars above
     let extractTabStops = bodyTree => {
-      for (const segment of bodyTree) {
+      for (let segment of bodyTree) {
         if (segment.index != null) {
           let {index, content, substitution} = segment
           if (index === 0) { index = Infinity; }
           const start = [row, column]
           extractTabStops(content)
           const range = new Range(start, [row, column])
-          const tabStop = this.tabStopList.findOrCreate({
+          const tabStop = tabStopList.findOrCreate({
             index,
             snippet: this
           })
           tabStop.addInsertion({ range, substitution })
-        } else if (typeof segment === 'string') {
-          bodyText.push(segment)
-          var segmentLines = segment.split('\n')
-          column += segmentLines.shift().length
-          let nextLine
-          while ((nextLine = segmentLines.shift()) != null) {
-            row += 1
-            column = nextLine.length
+        } else {
+          if (segment.variable != undefined) {
+            debugger
+            const value = this.variableResolver.resolve({ name: segment.variable })
+            if (value === undefined) {
+              if (segment.content) {
+                extractTabStops(segment.content)
+              }
+            } else {
+              segment = value
+            }
+          }
+
+          if (typeof segment === 'string') {
+            bodyText.push(segment)
+            var segmentLines = segment.split('\n')
+            column += segmentLines.shift().length
+            let nextLine
+            while ((nextLine = segmentLines.shift()) != null) {
+              row += 1
+              column = nextLine.length
+            }
           }
         }
       }
     }
 
-    extractTabStops(bodyTree)
+    extractTabStops(this.bodyTree)
     this.lineCount = row + 1
-    this.insertions = this.tabStopList.getInsertions()
+    this.insertions = tabStopList.getInsertions()
 
-    return bodyText.join('')
+    return { body: bodyText.join(''), tabStopList }
   }
 }

lib/snippets.js

@@ -9,6 +9,7 @@ const ScopedPropertyStore = require('scoped-property-store')
 const Snippet = require('./snippet')
 const SnippetExpansion = require('./snippet-expansion')
 const EditorStore = require('./editor-store')
+const VariableResolver = require('./variable-resolver')
 const {getPackageRoot} = require('./helpers')
 
 module.exports = {
@@ -19,6 +20,7 @@ module.exports = {
     this.snippetsByPackage = new Map
     this.parsedSnippetsById = new Map
     this.editorMarkerLayers = new WeakMap
+    this.variableResolver = new VariableResolver
 
     this.scopedPropertyStore = new ScopedPropertyStore
     // The above ScopedPropertyStore will store the main registry of snippets.
@@ -418,7 +420,7 @@ module.exports = {
     if (snippet == null) {
       let {id, prefix, name, body, bodyTree, description, descriptionMoreURL, rightLabelHTML, leftLabel, leftLabelHTML} = attributes
       if (bodyTree == null) { bodyTree = this.getBodyParser().parse(body) }
-      snippet = new Snippet({id, name, prefix, bodyTree, description, descriptionMoreURL, rightLabelHTML, leftLabel, leftLabelHTML, bodyText: body})
+      snippet = new Snippet({id, name, prefix, bodyTree, description, descriptionMoreURL, rightLabelHTML, leftLabel, leftLabelHTML, bodyText: body, variableResolver: this.variableResolver})
       this.parsedSnippetsById.set(attributes.id, snippet)
     }
     return snippet
@@ -624,7 +626,7 @@ module.exports = {
     if (cursor == null) { cursor = editor.getLastCursor() }
     if (typeof snippet === 'string') {
       const bodyTree = this.getBodyParser().parse(snippet)
-      snippet = new Snippet({name: '__anonymous', prefix: '', bodyTree, bodyText: snippet})
+      snippet = new Snippet({name: '__anonymous', prefix: '', bodyTree, bodyText: snippet, variableResolver: this.variableResolver})
     }
     return new SnippetExpansion(snippet, editor, cursor, this)
   },
@@ -662,5 +664,9 @@ module.exports = {
   onUndoOrRedo (editor, isUndo) {
     const activeExpansions = this.getExpansions(editor)
     activeExpansions.forEach(expansion => expansion.onUndoOrRedo(isUndo))
+  },
+
+  provideVariableResolver (resolver) {
+    this.variableResolver.add(resolver)
   }
 }

lib/variable-resolver.js

@@ -0,0 +1,27 @@
+module.exports = class VariableResolver {
+  constructor (resolvers = new Map) {
+    this.resolvers = new Map([
+      ["CLIPBOARD", resolveClipboard],
+      ...resolvers
+    ])
+  }
+
+  add (variable, resolver) {
+    this.resolvers.set(variable, resolver)
+  }
+
+  resolve (params) {
+
+    const resolver = this.resolvers.get(params.name)
+
+    if (resolver) {
+      return resolver(params)
+    }
+
+    return undefined
+  }
+}
+
+function resolveClipboard () {
+  return atom.clipboard.read()
+}

package.json

@@ -25,6 +25,12 @@
       "versions": {
         "0.1.0": "provideSnippets"
       }
+    },
+    "snippetsVariableResolver": {
+      "description": "Provide custom functions to resolve snippet variables.",
+      "versions": {
+        "0.0.0": "provideVariableResolver"
+      }
     }
   },
   "devDependencies": {