diff --git a/docs/contents/demo.md b/docs/contents/demo.md
index 3d66befb..d5fbc7e6 100644
--- a/docs/contents/demo.md
+++ b/docs/contents/demo.md
@@ -138,6 +138,59 @@ This way, you can pass a informative path with plots for which informative capti
 To define the labels and/or captions manually, see @sec:labels-captions.
 For showing multiple plots, see @sec:plots.
 
+Most things can be done via functions.
+However, defining a struct is not possible, because `@sco` cannot locate the struct definition inside the module.
+Therefore, it is also possible to pass code and specify that you want to evaluate and show code (sc) without showing the output:
+
+<pre>
+```jl
+sc("
+struct Point
+    x
+    y
+end
+")
+```
+</pre>
+
+```jl
+sc("
+struct Point
+    x
+    y
+end
+")
+```
+
+and show code and output (sco).
+For example,
+
+<pre>
+```jl
+sco("p = Point(1, 2)")
+```
+</pre>
+
+shows as
+
+```jl
+sco("p = Point(1, 2)")
+```
+
+Note that this is starting to look a lot like R Markdown where the syntax would be something like
+
+<pre>
+```{r, results='hide'}
+x = rnorm(100)
+```
+</pre>
+
+I guess that there is no perfect way here.
+The benefit of evaluating the user input directly, as Books.jl is doing, seems to be that it is more extensible if I'm not mistaken.
+Possibly, the reasoning is that R Markdown needs to convert the output directly, whereas Julia's better type system allows for converting in much later stages, but I'm not sure.
+
+> **Tip**: After you run `gen(; M)` with the `Point` struct defined above, the struct will be available in your REPL.
+
 ## Labels and captions {#sec:labels-captions}
 
 To set labels and captions, wrap your object in `Options`:
diff --git a/src/Books.jl b/src/Books.jl
index 0aad7371..39c7ffe2 100644
--- a/src/Books.jl
+++ b/src/Books.jl
@@ -12,7 +12,7 @@ using Requires
 using pandoc_jll
 using pandoc_crossref_jll
 
-const PROJECT_ROOT = pkgdir(Books)
+const PROJECT_ROOT = string(pkgdir(Books))::String
 const GENERATED_DIR = "_gen"
 const DEFAULTS_DIR = joinpath(PROJECT_ROOT, "defaults")
 const BUILD_DIR = "_build"
@@ -31,7 +31,7 @@ include("generate.jl")
 export html, pdf, docx, build_all
 export code, ImageOptions, Options
 export code_block
-export @sc, CodeAndFunction, @sco
+export @sc, sc, CodeAndFunction, @sco, sco
 export gen
 export serve
 
diff --git a/src/build.jl b/src/build.jl
index 7749d040..ab03aeb3 100644
--- a/src/build.jl
+++ b/src/build.jl
@@ -117,7 +117,7 @@ function html(; project="default", extra_head="")
     copy_extra_directories(project)
     url_prefix = is_ci() ? ci_url_prefix(project) : ""
     c = config(project, "contents")
-    write_html_pages(url_prefix, c, pandoc_html(project), extra_head)
+    write_html_pages(url_prefix, pandoc_html(project), extra_head)
 end
 
 """
diff --git a/src/generate.jl b/src/generate.jl
index b090c23a..e057e3c9 100644
--- a/src/generate.jl
+++ b/src/generate.jl
@@ -14,6 +14,10 @@ extract_expr_example() = """
     ```jl
     foo(3)
     ```
+    ```jl
+    foo(3)
+    bar
+    ```
     ipsum `jl bar()` dolar
     """
 
@@ -27,8 +31,9 @@ Here, `s` is the contents of a Markdown file.
 julia> s = Books.extract_expr_example();
 
 julia> Books.extract_expr(s)
-2-element Vector{String}:
+3-element Vector{String}:
  "foo(3)"
+ "foo(3)\\nbar"
  "bar()"
 ```
 """
@@ -36,7 +41,7 @@ function extract_expr(s::AbstractString)::Vector
     codeblock_pattern = r"```jl\s*([\w\W]*?)```"
     matches = eachmatch(codeblock_pattern, s)
     function clean(m)
-        m = m[1]
+        m = m[1]::SubString{String}
         m = strip(m)
         m = string(m)::String
     end
@@ -49,7 +54,7 @@ function extract_expr(s::AbstractString)::Vector
 
     function check_parse_errors(expr)
         try
-            Meta.parse(expr)
+            Meta.parse("begin $expr end")
         catch e
             error("Exception occured when trying to parse `$expr`")
         end
@@ -100,7 +105,6 @@ julia> Books.method_name("Options(foo(); caption='b')")
 function method_name(expr::String)
     remove_macros(expr) = replace(expr, r"@[\w\_]*" => "")
     expr = remove_macros(expr)
-    # These rewrites are not reversible, because they do not have to be.
     expr = replace(expr, '(' => '_')
     expr = replace(expr, ')' => "")
     expr = replace(expr, ';' => "_")
@@ -119,23 +123,17 @@ Escape an expression to the corresponding path.
 The logic in this method should match the logic in the Lua filter.
 """
 function escape_expr(expr::String)
-    replace_map = [
-        '(' => "-ob-",
-        ')' => "-cb-",
-        '"' => "-dq-",
-        ':' => "-fc-",
-        ';' => "-sc-",
-        '@' => "-ax-"
-    ]
-    escaped = reduce(replace, replace_map; init=expr)
+    escaped = 60 < length(expr) ? expr[1:60] : expr
+    escaped = replace(escaped, r"([^a-zA-Z0-9]+)" => "_")
     joinpath(GENERATED_DIR, "$escaped.md")
 end
 
 function evaluate_and_write(M::Module, expr::String)
     path = escape_expr(expr)
-    println("Writing output of `$expr` to $path")
+    expr_info = replace(expr, '\n' => "\\n")
+    println("Writing output of `$expr_info` to $path")
 
-    ex = Meta.parse(expr)
+    ex = Meta.parse("begin $expr end")
     out = Core.eval(M, ex)
     out = convert_output(expr, path, out)
     out = string(out)::String
@@ -148,7 +146,8 @@ function evaluate_and_write(f::Function)
     function_name = Base.nameof(f)
     expr = "$(function_name)()"
     path = escape_expr(expr)
-    println("Writing output of `$expr` to $path")
+    expr_info = replace(expr, '\n' => "\\n")
+    println("Writing output of `$expr_info` to $path")
     out = f()
     out = convert_output(expr, path, out)
     out = string(out)::String
@@ -158,11 +157,11 @@ function evaluate_and_write(f::Function)
 end
 
 """
-    evaluate_include(expr::String, M::Module, fail_on_error::Bool)
+    evaluate_include(expr::String, M, fail_on_error::Bool)
 
 For a `path` included in a Markdown file, run the corresponding function and write the output to `path`.
 """
-function evaluate_include(expr::String, M::Module, fail_on_error::Bool)
+function evaluate_include(expr::String, M, fail_on_error::Bool)
     if isnothing(M)
         # This code isn't really working.
         M = caller_module()
@@ -193,7 +192,7 @@ function expand_path(p)
 end
 
 """
-    gen(paths::Vector{String}; M=Main, fail_on_error=false, project="default")
+    gen(paths::Vector; M=Main, fail_on_error=false, project="default")
 
 Populate the files in `$(Books.GENERATED_DIR)/` by calling the required methods.
 These methods are specified by the filename and will output to that filename.
@@ -209,8 +208,10 @@ After calling the methods, this method will also call `html()` to update the sit
     just load them inside your REPL (module `Main`) and call `gen()`.
     For example, you can define `M = YourModule` to shorten calls to methods in your module.
 """
+
 function gen(paths::Vector{String};
         M=Main, fail_on_error=false, project="default", call_html=true)
+
     mkpath(GENERATED_DIR)
     paths = [contains(dirname(p), "contents") ? p : expand_path(p) for p in paths]
     included_expr = vcat([extract_expr(read(p, String)) for p in paths]...)
@@ -225,7 +226,7 @@ end
 """
     gen(path::AbstractString; kwargs...)
 
-Convenience method for passing `path::AbstractString` instead of `paths::Vector{AbstractString}`.
+Convenience method for passing `path::AbstractString` instead of `paths::Vector`.
 """
 function gen(path::AbstractString; kwargs...)
     path = string(path)::String
diff --git a/src/html.jl b/src/html.jl
index f7fefada..b7279583 100644
--- a/src/html.jl
+++ b/src/html.jl
@@ -2,14 +2,14 @@ import YAML
 import URIs
 
 """
-    split_keepdelim(str::AbstractString, dlm::Regex)
+    split_keepdelim(str::AbstractString, delim::Regex)
 
 Split on regex while keeping the matches.
 Based on https://github.com/JuliaLang/julia/issues/20625#issuecomment-581585151.
 """
-function split_keepdelim(str::AbstractString, dlm::Regex)
-    dlm = string(dlm)[3:end-1]
-    rx = Regex("(?=$dlm)")
+function split_keepdelim(str::AbstractString, delim::Regex)
+    delim = string(delim)[3:end-1]
+    rx = Regex("(?=$delim)")
     split(str, rx)
 end
 
@@ -79,7 +79,7 @@ function section_infos(text)
     for line in lines
         m = match(numbered_rx, line)
         if !isnothing(m)
-            number, id = m.captures 
+            number, id = m.captures
             line_end = split(line, '>')[end-1]
             text = line_end[nextind(line_end, 0, 2):prevind(line_end, end, 4)]
             tuple = (num = number, id = id, text = lstrip(text))
@@ -116,7 +116,7 @@ end
 function html_href(text, link, level)
     threshold = 33
     if threshold < length(text)
-        shortened = text[1:threshold]
+        shortened = text[1:threshold]::String
         text = shortened * ".."
     end
     """<a class="menu-level-$level" href="$link">$text</a>"""
@@ -139,7 +139,7 @@ end
 
 Menu including numbered sections.
 """
-function add_menu(splitted=split_html())
+function add_menu(splitted)
     head, bodies, foot = splitted
     data = pandoc_metadata()
     title = data["title"]
@@ -224,7 +224,7 @@ function add_extra_head(head, extra_head::AbstractString)
     replace(head, before => after)
 end
 
-function html_pages(chs=chapters(), h=pandoc_html(), extra_head="")
+function html_pages(h, extra_head="")
     head, menu, bodies, foot = add_menu(split_html(h))
     head = add_extra_head(head, extra_head)
     ids_texts = html_page_name.(bodies)
@@ -247,7 +247,7 @@ function map_ids(names, pages)
         html = page
         matches = eachmatch(rx, html)
         for m in matches
-            capture = first(m.captures)
+            capture = first(m.captures)::SubString{String}
             if startswith(capture, "sec:")
                 key = '#' * capture
                 mapping[key] = name
@@ -269,7 +269,7 @@ function fix_links(names, pages, url_prefix)
     updated_pages = []
     function fix_page(name, page)
         function replace_match(s)
-            capture = first(match(rx, s).captures)
+            capture = first(match(rx, s).captures)::SubString{String}
             if startswith(capture, "#sec:")
                 page_link = mapping[capture]
                 return uncapture("$url_prefix/$page_link.html$capture")
@@ -290,9 +290,9 @@ function fix_links(names, pages, url_prefix)
     (names, fixed_pages)
 end
 
-function write_html_pages(url_prefix, chs=chapters(), h=pandoc_html(), extra_head="")
+function write_html_pages(url_prefix, h::AbstractString, extra_head="")
     h = fix_image_urls(h, url_prefix)
-    names, pages = html_pages(chs, h, extra_head)
+    names, pages = html_pages(h, extra_head)
     names, pages = fix_links(names, pages, url_prefix)
     for (i, (name, page)) in enumerate(zip(names, pages))
         name = i == 1 ? "index" : name
diff --git a/src/include-codeblocks.lua b/src/include-codeblocks.lua
index 1b26034b..7d1c609f 100644
--- a/src/include-codeblocks.lua
+++ b/src/include-codeblocks.lua
@@ -36,19 +36,18 @@ local function shift_headings(blocks, shift_by)
 end
 
 --- Return path of the markdown file for the string `s` given by the user.
+---
+--- We can just drop a lot of info because it will probably still be unique.
+--- Otherwise, Julia can detect duplicate filenames and throw an error.
+---
 --- Ensure that this logic corresponds to the logic inside Books.jl.
+---
 local md_path
 function md_path(s)
-  -- Escape all weird characters to ensure they can be in the file.
-  -- This yields very weird names, but luckily the code is only internal.
-  escaped = s
-  escaped = escaped:gsub("%(", "-ob-")
-  escaped = escaped:gsub("%)", "-cb-")
-  escaped = escaped:gsub("\"", "-dq-")
-  escaped = escaped:gsub(":", "-fc-")
-  escaped = escaped:gsub(";", "-sc-")
-  escaped = escaped:gsub("@", "-ax-")
-  path_sep = package.config:sub(1,1)
+  escaped = string.sub(s, 1, 60)
+  escaped = escaped:gsub("([^a-zA-Z0-9]+)", "_")
+  -- Platform independent path separator.
+  path_sep = package.config:sub(1, 1)
   path = "_gen" .. path_sep .. escaped .. ".md"
   return path
 end
@@ -86,48 +85,38 @@ function transclude_codeblock(cb)
   local buffer_last_heading_level = last_heading_level
 
   local blocks = List:new()
-  for line in cb.text:gmatch('[^\n]+') do
-    if line:sub(1,2) ~= '//' then
-
-      path = md_path(line)
-      if 100 < path:len() then
-        msg = "ERROR: The text `" .. line .. "` is too long to be converted to a filename"
-        msg = { pandoc.CodeBlock(msg) }
-        blocks:extend(msg)
-        -- Lua has no continue.
-        goto skip_to_next
-      end
-
-      local fh = io.open(path)
-      if not fh then
-        not_found_error(line, path, '```')
-        suggestion = "Did you run `gen(; M)` where `M = YourModule`?\n"
-        msg = "ERROR: Cannot find file at " .. path .. " for `" .. line .. "`."
-        msg = msg .. ' ' .. suggestion
-        msg = { pandoc.CodeBlock(msg) }
-        blocks:extend(msg)
-      else
-        local text = fh:read("*a")
-        local contents = pandoc.read(text, format).blocks
-        last_heading_level = 0
-        -- recursive transclusion
-        contents = pandoc.walk_block(
-          -- Here, the contents is added as an Any block.
-          -- Then, the filter is applied again recursively because
-          -- the included file could contain an include again!
-          pandoc.Div(contents),
-          { Header = update_last_level, CodeBlock = transclude }
-          ).content
-        --- reset to level before recursion
-        last_heading_level = buffer_last_heading_level
-        contents = shift_headings(contents, shift_heading_level_by)
-        -- Note that contents has type List.
-        blocks:extend(contents)
-        fh:close()
-      end
-    end
-    ::skip_to_next::
+
+
+  path = md_path(cb.text)
+
+  local fh = io.open(path)
+  if not fh then
+    not_found_error(cb.text, path, '```')
+    suggestion = "Did you run `gen(; M)` where `M = YourModule`?\n"
+    msg = "ERROR: Cannot find file at " .. path .. " for `" .. cb.text .. "`."
+    msg = msg .. ' ' .. suggestion
+    msg = { pandoc.CodeBlock(msg) }
+    blocks:extend(msg)
+  else
+    local text = fh:read("*a")
+    local contents = pandoc.read(text, format).blocks
+    last_heading_level = 0
+    -- recursive transclusion
+    contents = pandoc.walk_block(
+      -- Here, the contents is added as an Any block.
+      -- Then, the filter is applied again recursively because
+      -- the included file could contain an include again!
+      pandoc.Div(contents),
+      { Header = update_last_level, CodeBlock = transclude }
+      ).content
+    --- reset to level before recursion
+    last_heading_level = buffer_last_heading_level
+    contents = shift_headings(contents, shift_heading_level_by)
+    -- Note that contents has type List.
+    blocks:extend(contents)
+    fh:close()
   end
+  ::skip_to_next::
   return blocks
 end
 
diff --git a/src/include-files.lua b/src/include-files.lua
deleted file mode 100644
index f685ec00..00000000
--- a/src/include-files.lua
+++ /dev/null
@@ -1,92 +0,0 @@
---- include-files.lua – filter to include Markdown files
----
---- Copyright: © 2019–2020 Albert Krewinkel
---- License:   MIT – see LICENSE file for details
-
--- pandoc's List type
-local List = require 'pandoc.List'
-
---- Get include auto mode
-local include_auto = false
-function get_vars (meta)
-  if meta['include-auto'] then
-    include_auto = true
-  end
-end
-
---- Keep last heading level found
-local last_heading_level = 0
-function update_last_level(header)
-  last_heading_level = header.level
-end
-
---- Shift headings in block list by given number
-local function shift_headings(blocks, shift_by)
-  if not shift_by then
-    return blocks
-  end
-
-  local shift_headings_filter = {
-    Header = function (header)
-      header.level = header.level + shift_by
-      return header
-    end
-  }
-
-  return pandoc.walk_block(pandoc.Div(blocks), shift_headings_filter).content
-end
-
---- Filter function for code blocks
-local transclude
-function transclude (cb)
-  -- ignore code blocks which are not of class "include".
-  if not cb.classes:includes 'include' then
-    return
-  end
-
-  -- Markdown is used if this is nil.
-  local format = cb.attributes['format']
-
-  -- Attributes shift headings
-  local shift_heading_level_by = 0
-  local shift_input = cb.attributes['shift-heading-level-by']
-  if shift_input then
-    shift_heading_level_by = tonumber(shift_input)
-  else
-    if include_auto then
-      -- Auto shift headings
-      shift_heading_level_by = last_heading_level
-    end
-  end
-
-  --- keep track of level before recusion
-  local buffer_last_heading_level = last_heading_level
-
-  local blocks = List:new()
-  for line in cb.text:gmatch('[^\n]+') do
-    if line:sub(1,2) ~= '//' then
-      local fh = io.open(line)
-      if not fh then
-        io.stderr:write("Cannot open file " .. line .. " | Skipping includes\n")
-      else
-        local contents = pandoc.read(fh:read '*a', format).blocks
-        last_heading_level = 0
-        -- recursive transclusion
-        contents = pandoc.walk_block(
-          pandoc.Div(contents),
-          { Header = update_last_level, CodeBlock = transclude }
-          ).content
-        --- reset to level before recursion
-        last_heading_level = buffer_last_heading_level
-        blocks:extend(shift_headings(contents, shift_heading_level_by))
-        fh:close()
-      end
-    end
-  end
-  return blocks
-end
-
-return {
-  { Meta = get_vars },
-  { Header = update_last_level, CodeBlock = transclude }
-}
diff --git a/src/showcode.jl b/src/showcode.jl
index 93fd32d6..e6a5c0cc 100644
--- a/src/showcode.jl
+++ b/src/showcode.jl
@@ -38,7 +38,6 @@ end
 function convert_output(expr, path, cf::CodeAndFunction)
     code = cf.code
     f = cf.f
-    println("Running $(f)() for $path")
     out = f()
     out = convert_output(expr, path, out)
     """
@@ -46,3 +45,50 @@ function convert_output(expr, path, cf::CodeAndFunction)
     $out
     """
 end
+
+
+"""
+    CodeAndOutput(code::AbstractString)
+
+This struct is used by [`sco`](@ref).
+"""
+struct CodeAndOutput
+    code::AbstractString
+end
+
+"""
+    eval_convert(expr::AbstractString)
+
+Evaluate `expr` and convert the output.
+This should be evaluated inside the correct module since it is typically called
+inside `Core.eval(M, ex)` in `generate.jl`.
+"""
+function eval_convert(expr::AbstractString, M)
+    ex = Meta.parse(expr)
+    out = Core.eval(M, ex)
+    out = convert_output(expr, nothing, out)
+end
+
+"""
+    sco(expr::AbstractString; M=Main)
+
+Show code and output for `expr`.
+"""
+function sco(expr::AbstractString; M=Main)
+    out = eval_convert(expr, M)
+    code = code_block(lstrip(expr))
+    """
+    $code
+    $out
+    """
+end
+
+"""
+    sc(expr::AbstractString; M=Main)
+
+Show only code for `expr`, that is, evaluate `expr` but hide the output.
+"""
+function sc(expr::AbstractString; M=Main)
+    eval_convert(expr, M)
+    code_block(lstrip(expr))
+end