use keyword

src/main/grammars/Elvish.bnf

@@ -53,6 +53,7 @@
     KEYWORD_TRY="try"
     KEYWORD_DEL="del"
     KEYWORD_FN="fn"
+    KEYWORD_USE="use"
     CONTINUATION="regexp:[\\][\r|\n]"
   ]
 }
@@ -114,7 +115,7 @@ BracedSep ::= (Space | EOL)* [ ',' ] (Space | EOL)*
 
 // Special Commands
 
-private SpecialCommand ::= DeleteCommand | LogicCommand | IfCommand | WhileCommand | ForCommand | TryCommand | FnCommand
+private SpecialCommand ::= DeleteCommand | UseCommand | LogicCommand | IfCommand | WhileCommand | ForCommand | TryCommand | FnCommand
 
 DeleteCommand ::= KEYWORD_DEL CommandSep* Variable Index*
 LogicCommand ::= LogicCMD (CommandSep* argument)* CommandSep*
@@ -129,4 +130,5 @@ Collection ::= List | Map | VariableRef | ExceptionCapture | OutputCapture
 TryCommand ::= KEYWORD_TRY Space OPEN_BRACE Chunk CLOSE_BRACE (Space ExceptBlock)? (Space ElseBlock)? (Space FinallyBlock)?
 ExceptBlock ::= KEYWORD_EXCEPT Space Variable Space OPEN_BRACE Chunk CLOSE_BRACE
 FinallyBlock ::= KEYWORD_FINALLY Space OPEN_BRACE Chunk CLOSE_BRACE
-FnCommand ::= KEYWORD_FN Space Variable Space LambdaArguments? OPEN_BRACE Chunk CLOSE_BRACE
+FnCommand ::= KEYWORD_FN Space Variable Space LambdaArguments? OPEN_BRACE Chunk CLOSE_BRACE
+UseCommand ::= KEYWORD_USE Space Bareword

src/main/grammars/Elvish.flex

@@ -53,6 +53,7 @@ KEYWORD_IF = if
 KEYWORD_TRY = try
 KEYWORD_DEL = del
 KEYWORD_FN = fn
+KEYWORD_USE = use
 STRING_CMP_BUILTINS=(([<>=!]=)|[<>])s
 NUMERIC_CMP_BUILTINS=(([<>=!]=)|[<>])
 VARIABLE_CHAR=[[0-9a-zA-Z\-_:~]||[[\u0080-\uFFFF]&&\p{Print}]] // see parse/parse.go:713 (allowedInVariableName())
@@ -109,6 +110,7 @@ WHITESPACE=({INLINE_WHITESPACE_CHAR}|{EOL})+
   {KEYWORD_FN}              { return ElvishTypes.KEYWORD_FN; }
   {KEYWORD_TRY}             { return ElvishTypes.KEYWORD_TRY; }
   {KEYWORD_DEL}             { return ElvishTypes.KEYWORD_DEL; }
+  {KEYWORD_USE}             { return ElvishTypes.KEYWORD_USE; }
   {VARIABLE_CHAR}+          { return ElvishTypes.VARIABLE_CHAR; }
   {BAREWORD_CHAR}+          { return ElvishTypes.BAREWORD_CHAR; }
   {COMMAND_BAREWORD_CHAR}+  { return ElvishTypes.COMMAND_BAREWORD_CHAR; }

src/main/kotlin/com/github/sblundy/elvish/ElvishSyntaxHighlighter.kt

@@ -32,6 +32,7 @@ class ElvishSyntaxHighlighter : SyntaxHighlighterBase() {
                 ElvishTypes.KEYWORD_FOR,
                 ElvishTypes.KEYWORD_IF,
                 ElvishTypes.KEYWORD_TRY,
+                ElvishTypes.KEYWORD_USE,
                 ElvishTypes.KEYWORD_WHILE -> KEYWORD_KEYS
             ElvishTypes.OPEN_BRACKET, ElvishTypes.CLOSE_BRACKET -> BRACKETS_KEYS
             ElvishTypes.OPEN_BRACE, ElvishTypes.CLOSE_BRACE -> BRACES_KEYS

src/test/resources/com/github/sblundy/elvish/lang/use-nested.elv

@@ -0,0 +1 @@
+use x:y:z

src/test/resources/com/github/sblundy/elvish/lang/use-nested.txt

@@ -0,0 +1,7 @@
+Elvish File
+  ElvishChunkImpl(CHUNK)
+    ElvishUseCommandImpl(USE_COMMAND)
+      PsiElement(ElvishTokenType.use)('use')
+      PsiElement(ElvishTokenType.INLINE_WHITESPACE)(' ')
+      ElvishBarewordImpl(BAREWORD)
+        PsiElement(ElvishTokenType.VARIABLE_CHAR)('x:y:z')

src/test/resources/com/github/sblundy/elvish/lang/use-path.elv

@@ -0,0 +1 @@
+use x/y/z

src/test/resources/com/github/sblundy/elvish/lang/use-path.txt

@@ -0,0 +1,11 @@
+Elvish File
+  ElvishChunkImpl(CHUNK)
+    ElvishUseCommandImpl(USE_COMMAND)
+      PsiElement(ElvishTokenType.use)('use')
+      PsiElement(ElvishTokenType.INLINE_WHITESPACE)(' ')
+      ElvishBarewordImpl(BAREWORD)
+        PsiElement(ElvishTokenType.VARIABLE_CHAR)('x')
+        PsiElement(ElvishTokenType.BAREWORD_CHAR)('/')
+        PsiElement(ElvishTokenType.VARIABLE_CHAR)('y')
+        PsiElement(ElvishTokenType.BAREWORD_CHAR)('/')
+        PsiElement(ElvishTokenType.VARIABLE_CHAR)('z')

src/test/resources/com/github/sblundy/elvish/lang/use.elv

@@ -0,0 +1,3 @@
+use re
+
+re:find "x" $x

src/test/resources/com/github/sblundy/elvish/lang/use.txt

@@ -0,0 +1,27 @@
+Elvish File
+  ElvishChunkImpl(CHUNK)
+    ElvishUseCommandImpl(USE_COMMAND)
+      PsiElement(ElvishTokenType.use)('use')
+      PsiElement(ElvishTokenType.INLINE_WHITESPACE)(' ')
+      ElvishBarewordImpl(BAREWORD)
+        PsiElement(ElvishTokenType.VARIABLE_CHAR)('re')
+    ElvishPipelineSepImpl(PIPELINE_SEP)
+      PsiElement(ElvishTokenType.EOL)('\n')
+    ElvishPipelineSepImpl(PIPELINE_SEP)
+      PsiElement(ElvishTokenType.EOL)('\n')
+    ElvishHeadImpl(HEAD)
+      ElvishCommandBarewordImpl(COMMAND_BAREWORD)
+        PsiElement(ElvishTokenType.VARIABLE_CHAR)('re:find')
+    PsiElement(ElvishTokenType.INLINE_WHITESPACE)(' ')
+    ElvishArgumentImpl(ARGUMENT)
+      ElvishCompoundImpl(COMPOUND)
+        ElvishDoubleQuotedImpl(DOUBLE_QUOTED)
+          PsiElement(ElvishTokenType.")('"')
+          PsiElement(ElvishTokenType.TEXT)('x')
+          PsiElement(ElvishTokenType.")('"')
+    PsiElement(ElvishTokenType.INLINE_WHITESPACE)(' ')
+    ElvishArgumentImpl(ARGUMENT)
+      ElvishCompoundImpl(COMPOUND)
+        ElvishVariableRefImpl(VARIABLE_REF)
+          PsiElement(ElvishTokenType.$)('$')
+          PsiElement(ElvishTokenType.VARIABLE_CHAR)('x')