Strip single trailing newlines (#44)

* Strip single trailing newlines

* Fix build. Change from checkout@v2 to v3

* The latest version of rebar3 no longer supports OTP 23, moved to 24,25,26

* Added missing applications to the app.src file

.github/workflows/hex-publish.yml

@@ -10,7 +10,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Check out
-        uses: actions/checkout@v2
+        uses: actions/checkout@v3
 
       - name: Publish to Hex.pm
         uses: erlangpack/github-action@v3

.github/workflows/test.yml

@@ -13,14 +13,14 @@ jobs:
 
     strategy:
       matrix:
-        otp_version: [23,24,25]
+        otp_version: [24,25,26]
         os: [ubuntu-latest]
 
     container:
       image: erlang:${{ matrix.otp_version }}
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: Compile
         run: make
       - name: Test

README.md

@@ -499,6 +499,11 @@ when you are still writing the template:
 The expression value will be printed using `io_lib:format("~p", [ SomExpr ])`, then
 escaped and surrounded with `<pre>...</pre>`.
 
+Whitespace Handling
+-------------------
+
+- A single trailing newline is stripped, from the template, if present.
+- Other whitespace, like tabs, newlines and spaces are returned unchanged.
 
 License
 =======

src/template_compiler.app.src

@@ -6,7 +6,10 @@
   {applications, [
       kernel,
       stdlib,
-      crypto
+      crypto,
+      compiler,
+      syntax_tools,
+      zotonic_stdlib
   ]},
   {env,[
       {template_dir, {template_compiler, "templates"}}

src/template_compiler_scanner.erl

@@ -45,6 +45,8 @@
 
 -export([scan/1, scan/2]). 
 
+-define(IS_EOF(S),
+        (S =:= <<>> orelse S =:= <<"\n">> orelse S =:= <<"\r\n">>)).
 
 %%====================================================================
 %% API
@@ -138,20 +140,20 @@ identifier_to_keyword({Type, Pos, String}, {_PrevToken, Acc}) ->
     {Type, [{Type, Pos, String}|Acc]}.
 
 
-scan(<<>>, Scanned, _, in_text) ->
+scan(Eof, Scanned, _, in_text) when ?IS_EOF(Eof) ->
     {_Token, ScannedKeyword} = lists:foldr(fun identifier_to_keyword/2, {'$eof', []}, Scanned),
     {ok, lists:reverse(ScannedKeyword)};
 
-scan(<<>>, _Scanned, {SourceRef, _, _}, {in_comment, _}) ->
+scan(Eof, _Scanned, {SourceRef, _, _}, {in_comment, _}) when ?IS_EOF(Eof) ->
     {error, io_lib:format("Reached end of ~p inside a comment.", [SourceRef])};
 
-scan(<<>>, _Scanned, {SourceRef, _, _}, {in_trans, _}) ->
+scan(Eof, _Scanned, {SourceRef, _, _}, {in_trans, _}) when ?IS_EOF(Eof) ->
     {error, io_lib:format("Reached end of ~p inside a trans block.", [SourceRef])};
 
-scan(<<>>, _Scanned, {SourceRef, _, _}, {in_raw, _}) ->
+scan(Eof, _Scanned, {SourceRef, _, _}, {in_raw, _}) when ?IS_EOF(Eof) ->
     {error, io_lib:format("Reached end of ~p inside a raw block.", [SourceRef])};
 
-scan(<<>>, _Scanned, {SourceRef, _, _}, _) ->
+scan(Eof, _Scanned, {SourceRef, _, _}, _) when ?IS_EOF(Eof) ->
     {error, io_lib:format("Reached end of ~p inside a code block.", [SourceRef])};
 
 %%we just capture the {% raw %} {% endraw %} tags and pass on string between the tags as is

test/template_compiler_expr_SUITE.erl

@@ -93,7 +93,7 @@ undefined
 <<104,101,108,108,111,32,119,111,114,108,100>>
 atom
 [a,b,c]
-#{<<97>> => 1,<<98>> => 2}\n">> = iolist_to_binary(Bin1),
+#{<<97>> => 1,<<98>> => 2}">> = iolist_to_binary(Bin1),
     ok.
 
 expr_nested(_Config) ->

test/template_compiler_include_SUITE.erl

@@ -45,6 +45,13 @@ include_test(_Config) ->
 include_dynamic_test(_Config) ->
     {ok, Bin1} = template_compiler:render("include_dynamic.tpl", #{ t => "include_b.tpl" }, [], undefined),
     <<"abc">> = iolist_to_binary(Bin1),
+
+    {ok, Bin2} = template_compiler:render("include_dynamic.tpl", #{ t => "include_b_no_trailing_newline.tpl" }, [], undefined),
+    <<"abc">> = iolist_to_binary(Bin2),
+
+    {ok, Bin3} = template_compiler:render("include_dynamic.tpl", #{ t => "include_b_trailing_dos_newline.tpl" }, [], undefined),
+    <<"abc">> = iolist_to_binary(Bin3),
+
     ok.
 
 include_args_test(_Config) ->

test/test-data/include_b.tpl

@@ -1 +1 @@
-b
+b

test/test-data/include_b_no_trailing_newline.tpl

@@ -0,0 +1 @@
+b

test/test-data/include_b_trailing_dos_newline.tpl

@@ -0,0 +1 @@
+b