diff --git a/.travis.yml b/.travis.yml
--- a/.travis.yml
+++ b/.travis.yml
@@ -60,13 +60,13 @@
       echo "skipping yaml verification..."
     fi
   - stack build --test --bench --no-run-tests --no-run-benchmarks
+  - find -name atsfmt -executable
   - |
     if [ `uname` = "Darwin" ]
     then
       export BINPATH="$(find . -name atsfmt -perm 755 | tail -n1)"
     else
-      rm -rf .stack-work
-      export BINPATH="$(find -name atsfmt -executable | tail -n1 | head -n1)"
+      export BINPATH="$(find -name atsfmt -executable | tail -n1)"
     fi
   - echo $BINPATH
   - mv $BINPATH atsfmt-$TARGET
diff --git a/ats-format.cabal b/ats-format.cabal
--- a/ats-format.cabal
+++ b/ats-format.cabal
@@ -1,5 +1,5 @@
 name:                ats-format
-version:             0.1.0.2
+version:             0.1.0.3
 synopsis:            A source-code formatter for ATS
 description:         An opinionated source-code formatter for ATS (http://www.ats-lang.org/).
 homepage:            https://hub.darcs.net/vmchale/ats-format#readme
diff --git a/src/Language/ATS/Exec.hs b/src/Language/ATS/Exec.hs
--- a/src/Language/ATS/Exec.hs
+++ b/src/Language/ATS/Exec.hs
@@ -115,7 +115,8 @@
 fancyError = either (printFail . show . pretty) pure
 
 pick :: Program -> IO ()
-pick (Program (Just p) False nc _) = (genErr nc . parseATS . lexATS) =<< readFile p
-pick (Program Nothing _ nc False)  = (genErr nc . parseATS . lexATS) =<< getContents
-pick (Program Nothing _ _ True)    = defaultConfig ".atsfmt.toml"
-pick (Program (Just p) True _ _)   = inplace p (fmap printATS . fancyError . parseATS . lexATS)
+pick (Program (Just p) False nc _)  = (genErr nc . parseATS . lexATS) =<< readFile p
+pick (Program Nothing _ nc False)   = (genErr nc . parseATS . lexATS) =<< getContents
+pick (Program Nothing _ _ True)     = defaultConfig ".atsfmt.toml"
+pick (Program (Just p) True True _) = inplace p (fmap printATS . fancyError . parseATS . lexATS)
+pick (Program (Just p) True _ _)    = inplace p ((printCustom <=< fancyError) . parseATS . lexATS)
diff --git a/src/Language/ATS/Lexer.x b/src/Language/ATS/Lexer.x
--- a/src/Language/ATS/Lexer.x
+++ b/src/Language/ATS/Lexer.x
@@ -89,6 +89,7 @@
 tokens :-
 
     $white+                  ;
+    ^ "//".*                 { tok (\p s -> CommentLex p s) }
     "//".*                   ;
     @block_comment           ;
     "#define".*              { tok (\p s -> MacroBlock p s) }      
diff --git a/src/Language/ATS/Parser.y b/src/Language/ATS/Parser.y
--- a/src/Language/ATS/Parser.y
+++ b/src/Language/ATS/Parser.y
@@ -142,6 +142,7 @@
     cblock { CBlockLex _ $$ }
     ref { RefTok $$ }
     define { MacroBlock _ $$ }
+    lineComment { CommentLex _ $$ }
 
 %%
 
@@ -418,7 +419,7 @@
             | abstype identifier openParen FullArgs closeParen eq Type { AbsType $1 $2 $4 $7 }
             | datatype identifier eq Leaves { SumType $2 $4 }
             | dataprop identifier openParen FullArgs closeParen eq DataPropLeaves { DataProp $1 $2 $4 $7 }
-            -- | tkindef FunName eq string { TKind $1 $2 $4 }
+            | lineComment { Comment $1 }
             | define { Define $1 }
             | cblock { CBlock $1 }
             | lambda {% Left $ Expected $1 "Declaration" "lam" }
diff --git a/stack.yaml b/stack.yaml
--- a/stack.yaml
+++ b/stack.yaml
@@ -1,5 +1,5 @@
 ---
-resolver: nightly-2017-12-07
+resolver: lts-10.0
 packages:
   - '.'
 extra-deps: