a_star: don't crash on deserialization errors and limit static types

[nit.git] / src / highlight.nit

# This file is part of NIT ( http://www.nitlanguage.org ).
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

# Highlighting of Nit AST
module highlight

import frontend
import html
import pipeline
import astutil
import serialization

# Fully process a content as a nit source file.
fun hightlightcode(hl: HighlightVisitor, content: String): HLCode
do
        # Prepare a stand-alone tool context
        var tc = new ToolContext
        tc.nit_dir = tc.locate_nit_dir # still use the common lib to have core
        tc.keep_going = true # no exit, obviously
        tc.opt_warn.value = -1 # no output, obviously

        # Prepare an stand-alone model and model builder.
        # Unfortunately, models are enclosing and append-only.
        # There is no way (yet?) to have a shared module `core` with
        # isolated and throwable user modules.
        var model = new Model
        var mb = new ModelBuilder(model, tc)

        # Parse the code
        var source = new SourceFile.from_string("", content + "\n")
        var lexer = new Lexer(source)
        var parser = new Parser(lexer)
        var tree = parser.parse

        var hlcode = new HLCode(hl, content, source)

        # Check syntax error
        var eof = tree.n_eof
        if eof isa AError then
                mb.error(eof, eof.message)
                hl.hightlight_source(source)
                return hlcode
        end
        var amodule = tree.n_base.as(not null)

        # Load the AST as a module in the model
        # Then process it
        mb.load_rt_module(null, amodule, "")
        mb.run_phases

        # Highlight the processed module
        hl.enter_visit(amodule)
        return hlcode
end

# A standalone highlighted piece of code
class HLCode
        super Serializable

        # The highlighter used
        var hl: HighlightVisitor

        # The raw code source
        var content: String

        # The pseudo source-file
        var source: SourceFile

        # JavaScript code to update an existing codemirror editor.
        fun code_mirror_update: Template
        do

                var res = new Template
                res.add """
        function nitmessage() {
                editor.operation(function(){
                        for (var i = 0; i < widgets.length; ++i)
                              editor.removeLineWidget(widgets[i]);
                        widgets.length = 0;
"""

                for m in source.messages do
                        res.add """
                        var l = document.createElement("div");
                        l.className = "lint-error"
                        l.innerHTML = "<span class='glyphicon glyphicon-warning-sign lint-error-icon'></span> {{{m.text.html_escape}}}";
                        var w = editor.addLineWidget({{{m.location.line_start-1}}}, l);
                        widgets.push(w);
"""
                end
                res.add """});}"""
                return res
        end

        redef fun core_serialize_to(v)
        do
                v.serialize_attribute("code", hl.html.write_to_string)
                var msgs = new Array[Map[String, Serializable]]
                for m in source.messages do
                        var o = new Map[String, Serializable]
                        msgs.add o
                        o["line"] = m.location.line_start-1
                        o["message"] = m.text
                end
                v.serialize_attribute("messages", msgs)
        end
end

# Visitor used to produce a HTML tree based on a AST on a `Source`
class HighlightVisitor
        # The root of the HTML hierarchy
        var html = new HTMLTag("span")

        # Should the HTML include a nested `<span class"{type_of_node}">` element for each `ANode` of the AST?
        #
        # Used to have a really huge and verbose HTML (mainly for debug)
        var with_ast = false is writable

        # Prefixes used in generated IDs for line `<span>` elements.
        # Useful if more than one highlighted code is present in the same HTML document.
        #
        # If set to the empty string, id for lines are disabled.
        #
        # Is `"L"` by default.
        var line_id_prefix = "L" is writable

        # The first line to generate, null if start at the first line
        var first_line: nullable Int = null is writable

        # The last line to generate, null if finish at the last line
        var last_line: nullable Int = null is writable

        # When highlighting a node, show its messages (errors, warnings), if any.
        #
        # default: true
        var show_messages = true is writable

        # When highlighting a node, attach a full popupable infobox, if any.
        #
        # If `false`, only a simple `title` tooltip is used.
        #
        # default: true
        var show_infobox = true is writable

        # A reference to an entity used in generated `<a>` elements.
        #
        # It is used to refer to some specific entities when generating links.
        # If `null` is returned, then no link are generated and `<a>` elements become `<span>`.
        #
        # By default, `null` is returned.
        # Clients are therefore encouraged to redefine the method in a subclass to control where entities should link to.
        fun hrefto(entity: MEntity): nullable String do return null

        init
        do
                html.add_class("nitcode")
        end

        # When highlighting a node, also consider the loose tokens around it.
        #
        # Loose tokens are tokens discarded from the AST but attached before
        # or after some non-loose tokens. See `Token::is_loose`.
        #
        # When this flag is set to `true`, the loose tokens that are before the
        # first token and after the last token are also highlighted.
        #
        # Default: false.
        var include_loose_tokens = false is writable

        # When highlighting a node, the first and the last lines are fully included.
        #
        # If the highlighted node starts (or ends) in the middle of a line,
        # this flags forces the whole line to be highlighted.
        #
        # Default: false
        var include_whole_lines = false is writable

        # The entry-point of the highlighting.
        # Will fill `html` with the generated HTML content.
        fun enter_visit(n: ANode)
        do
                n.parentize_tokens

                var f
                var l

                if n isa Token then
                        f = n
                        l = n
                else
                        assert n isa Prod
                        f = n.first_token
                        if f == null then return
                        l = n.last_token
                        if l == null then return
                end

                if include_loose_tokens then
                        if f.prev_looses.not_empty then f = f.prev_looses.first
                        if l.next_looses.not_empty then l = l.next_looses.last
                end

                var line = first_line
                if line != null then
                        while f.location.line_start < line do
                                f = f.next_token
                                if f == null then return
                        end
                end

                line = last_line
                if line != null then
                        while l.location.line_end > line do
                                l = l.prev_token
                                if l == null then return
                        end
                end

                if include_whole_lines then
                        f = f.first_real_token_in_line
                        l = l.last_real_token_in_line
                end

                htmlize(f, l)
        end

        private fun full_tag(anode: ANode, hv: HighlightVisitor): nullable HTMLTag
        do
                var tag = anode.make_tag(hv)
                if tag == null then return null
                var infobox = anode.infobox(hv)
                if infobox == null and anode isa Token then
                        var pa = anode.parent
                        if pa != null then
                                infobox = pa.decorate_tag(hv, tag, anode)
                        end
                end
                if infobox != null and not show_infobox then
                        tag.attr("title", infobox.title)
                        tag.classes.add "titled"
                        infobox = null
                end
                var messages = anode.location.messages
                if messages != null and show_messages then
                        tag.css("border-bottom", "solid 2px red")
                        if infobox == null then
                                infobox = new HInfoBox(hv, "Messages")
                        end
                        var c = infobox.new_dropdown("{messages.length} message(s)", "")
                        for m in messages do
                                c.open("li").append(m.text)
                        end
                end
                if infobox != null then
                        tag.attach_infobox(infobox)
                end
                return tag
        end

        # Highlight a full lexed source file.
        #
        # REQUIRE `source.first_token != null`
        fun hightlight_source(source: SourceFile)
        do
                htmlize(source.first_token.as(not null), null)
        end

        # Produce HTML between two tokens
        protected fun htmlize(first_token: Token, last_token: nullable Token)
        do
                var stack2 = new Array[HTMLTag]
                var stack = new Array[Prod]
                var line = 0
                var c: nullable Token = first_token
                var hv = self
                while c != null do
                        var starting

                        # Handle start of line
                        var cline = c.location.line_start
                        if cline != line then
                                # Handle starting block productions,
                                # Because c could be a detached token, get prods in
                                # the first AST token
                                var c0 = c.first_token_in_line
                                starting = null
                                if c0 != null then starting = c0.starting_prods
                                if starting != null then for p in starting do
                                        if not p.is_block then continue
                                        var tag = full_tag(p, hv)
                                        if tag == null then continue
                                        tag.add_class("foldable")
                                        stack2.add(html)
                                        html.add tag
                                        html = tag
                                        stack.add(p)
                                end

                                # Add a div for the whole line
                                var tag = new HTMLTag("span")
                                var p = line_id_prefix
                                if p != "" then tag.attrs["id"] = "{p}{cline}"
                                tag.classes.add "line"
                                stack2.add(html)
                                html.add tag
                                html = tag
                                line = cline
                        end

                        # Add the blank, verbatim
                        html.add_raw_html c.blank_before

                        # Handle starting span production
                        starting = c.starting_prods
                        if starting != null then for p in starting do
                                if not p.is_span then continue
                                var tag = full_tag(p, hv)
                                if tag == null then continue
                                stack2.add(html)
                                html.add tag
                                html = tag
                                stack.add(p)
                        end

                        # Add the token
                        if c isa TEol then
                                html.append "\n"
                        else
                                var tag = full_tag(c, hv)
                                if tag != null then html.add tag
                        end

                        # Handle ending span productions
                        var ending = c.ending_prods
                        if ending != null then for p in ending do
                                if not p.is_span then continue
                                if stack.is_empty or p != stack.last then continue
                                stack.pop
                                html = stack2.pop
                        end

                        # Handle end of line and end of file
                        var n = c.next_token
                        if c == last_token then n = null
                        if n == null or n.location.line_start != line  then
                                # closes the line div
                                html = stack2.pop

                                # close the block production divs
                                var c0 = c.last_token_in_line
                                ending = null
                                if c0 != null then ending = c0.ending_prods
                                if ending != null then for p in ending do
                                        if not p.is_block then continue
                                        if stack.is_empty or p != stack.last then continue
                                        stack.pop
                                        html = stack2.pop
                                end
                        end

                        c = n
                end
                if not stack2.is_empty then html = stack2.first
        end

        # Return a default CSS content related to CSS classes used in the `html` tree.
        # Could be inlined in the `.html` file of saved as a specific `.css` file.
        fun css_content: String
        do
                return """
.nitcode a { color: inherit; cursor:pointer; }
.nitcode .titled:hover { text-decoration: underline; } /* underline titles */
.nitcode .popupable:hover { text-decoration: underline; cursor:help; } /* underline titles */
.nitcode .foldable { display: block } /* for block productions*/
.nitcode .line{ display: block } /* for lines */
.nitcode .line:hover{ background-color: #FFFFE0; } /* current line */
.nitcode :target { background-color: #FFF3C2 } /* target highlight*/
/* lexical raw tokens. independent of usage or semantic: */
.nitcode .nc_c { color: gray; font-style: italic; } /* comment */
.nitcode .nc_d { color: #3D8127; font-style: italic; } /* documentation comments */
.nitcode .nc_k { font-weight: bold; } /* keyword */
.nitcode .nc_o {} /* operator */
.nitcode .nc_i {} /* standard identifier */
.nitcode .nc_t { color: #445588; font-weight: bold; } /* type/class identifier */
.nitcode .nc_a { color: #445588; font-style: italic; } /* old style attribute identifier */
.nitcode .nc_l { color: #009999; } /* char and number literal */
.nitcode .nc_s { color: #8F1546; } /* string literal */
/* syntactic token usage. added because of their position in the AST */
.nitcode .nc_ast { color: blue; } /* assert label */
.nitcode .nc_la { color: blue; } /* break/continue label */
.nitcode .nc_m { color: #445588; } /* module name */
/* syntactic groups */
.nitcode .nc_def { font-weight: bold; color: blue; } /* name used in a definition */
  .nitcode .nc_def.nc_a { color: blue; } /* name used in a attribute definition */
  .nitcode .nc_def.nc_t { color: blue; } /* name used in a class or vt definition */
.nitcode .nc_ss { color: #9E6BEB; } /* superstrings */
.nitcode .nc_cdef {} /* A whole class definition */
.nitcode .nc_pdef {} /* A whole property definition */
/* semantic token usage */
.nitcode .nc_v { font-style: italic; } /* local variable or parameter */
.nitcode .nc_vt { font-style: italic; } /* virtual type or formal type */

.nitcode .nc_error { border: 1px red solid;} /* not used */
.popover { max-width: 800px !important; }
"""
        end

        # Additional content to inject in the <head> tag
        # Note: does not include `css_content`; handle it yourself.
        fun head_content: String
        do
                return """<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/bootstrap/3.1.1/css/bootstrap.min.css">\n"""
        end

        # Additional content to inject just before the closing </body> tag
        fun foot_content: String
        do
                return """
<script src="http://code.jquery.com/jquery-1.11.0.min.js"></script>
<script src="http://netdna.bootstrapcdn.com/bootstrap/3.1.1/js/bootstrap.min.js"></script>
<script>$(".popupable").popover({html:true, placement:'top'})/*initialize bootstrap popover*/</script>"""
        end
end

redef class HTMLTag
        # Attach the infobox to the node by using BootStrap popover
        fun attach_infobox(infobox: HInfoBox)
        do
                classes.add("popupable")
                attrs["title"] = infobox.title
                var href = infobox.href
                if href != null then
                        attrs["data-title"] = """<a href="{{{href}}}">{{{infobox.title}}}</a>"""
                end
                attrs["data-content"] = infobox.content.write_to_string
                attrs["data-toggle"] = "popover"
        end
end


# A generic information container that can be used to decorate AST entities
class HInfoBox
        # The visitor used for contextualisation, if needed 
        var visitor: HighlightVisitor

        # A short title for the AST element
        var title: String

        # The primary link where the entity points
        # null if no link
        var href: nullable String = null

        # The content of the popuped infobox
        var content = new HTMLTag("div")

        # Append a new field in the popuped infobox
        fun new_field(title: String): HTMLTag
        do
                content.open("b").text(title)
                content.append(" ")
                var res = content.open("span")
                content.open("br")
                return res
        end

        # Append a new dropdown in the popuped content
        fun new_dropdown(title, text: String, text_is_html: nullable Bool): HTMLTag
        do
                content.add_raw_html """<div class="dropdown"> <a data-toggle="dropdown" href="#"><b>"""
                content.append(title)
                content.add_raw_html "</b> "
                if text_is_html == true then
                        content.add_raw_html(text)
                else content.append(text)
                content.add_raw_html """<span class="caret"></span></a>"""
                var res = content.open("ul").add_class("dropdown-menu").attr("role", "menu").attr("aria-labelledby", "dLabel")
                content.add_raw_html "</div>"
                return res
        end
end

##

# Model entity or whatever that can produce an infobox
interface HInfoBoxable
        # An new infobox documenting the entity
        fun infobox(v: HighlightVisitor): HInfoBox is abstract
end

redef class MDoc
        # Append an entry for the doc in the given infobox
        fun fill_infobox(res: HInfoBox)
        do
                if content.length < 2 then
                        res.new_field("doc").text(content.first)
                        return
                end
                var c = res.new_dropdown("doc", content.first)
                for x in content.iterator.skip_head(1) do
                        c.append x
                        c.add_raw_html "<br>"
                end
        end
end

redef class MEntity
        super HInfoBoxable

        # A HTML version of `to_s` with hyper-links.
        #
        # By default, `linkto_text(v, to_s)` is used, c.f. see `linkto_text`.
        #
        # For some complex entities, like generic types, multiple `<a>` and `<span>` elements can be generated.
        # E.g. `Array[Int]` might become `<a>Array</a>[<a>Int</a>]` with the correct `href` attributes
        # provided  by `v.hrefto`.
        fun linkto(v: HighlightVisitor): HTMLTag do return linkto_text(v, to_s)

        # Link to the `self` with a specific text.
        #
        # The whole text is linked with a single `<a>` element.
        #
        # The `href` used is provided by `v.hrefto`.
        # If `href` is null then a `<span>` element is used instead of `<a>`.
        fun linkto_text(v: HighlightVisitor, text: String): HTMLTag
        do
                var href = v.hrefto(self)
                if href == null then
                        return (new HTMLTag("span")).text(text)
                end
                return (new HTMLTag("a")).attr("href", href).text(text)
        end

        # Append an entry for the doc in the given infobox
        private fun add_doc_to_infobox(res: HInfoBox)
        do
                var mdoc = mdoc_or_fallback
                if mdoc != null then mdoc.fill_infobox(res)
        end
end

redef class MModule
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, "module {name}")
                res.href = v.hrefto(self)
                res.new_field("module").add(linkto(v))
                add_doc_to_infobox(res)
                if in_importation.greaters.length > 1 then
                        var c = res.new_dropdown("imports", "{in_importation.greaters.length-1} modules")
                        for x in in_importation.greaters do
                                if x == self then continue
                                c.open("li").add x.linkto(v)
                        end
                end
                return res
        end

        redef fun linkto(v) do return linkto_text(v, name)
end

redef class MClassDef
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, "class {mclass.name}")
                res.href = v.hrefto(self)
                if is_intro then
                        res.new_field("class").text(mclass.name)
                else
                        res.new_field("redef class").text(mclass.name)
                        res.new_field("intro").add mclass.intro.linkto_text(v, "in {mclass.intro_mmodule.to_s}")
                end
                add_doc_to_infobox(res)

                var in_hierarchy = self.in_hierarchy
                if in_hierarchy == null then return res

                if in_hierarchy.greaters.length > 1 then
                        var c = res.new_dropdown("hier", "super-classes")
                        for x in in_hierarchy.greaters do
                                if x == self then continue
                                if not x.is_intro then continue
                                c.open("li").add x.linkto(v)
                        end
                end
                if in_hierarchy.smallers.length > 1 then
                        var c = res.new_dropdown("hier", "sub-classes")
                        for x in in_hierarchy.smallers do
                                if x == self then continue
                                if not x.is_intro then continue
                                c.open("li").add x.linkto(v)
                        end
                end
                if mclass.mclassdefs.length > 1 then
                        var c = res.new_dropdown("redefs", "refinements")
                        for x in mclass.mclassdefs do
                                if x == self then continue
                                c.open("li").add x.linkto_text(v, "in {x.mmodule}")
                        end
                end
                return res
        end
end

redef class MPropDef
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, to_s)
                res.href = v.hrefto(self)
                if self isa MMethodDef then
                        var msignature = self.msignature
                        if msignature != null then res.new_field("fun").append(mproperty.name).add msignature.linkto(v)
                else if self isa MAttributeDef then
                        var static_mtype = self.static_mtype
                        if static_mtype != null then res.new_field("fun").append(mproperty.name).add static_mtype.linkto(v)
                else if self isa MVirtualTypeDef then
                        var bound = self.bound
                        if bound != null then res.new_field("add").append(mproperty.name).add bound.linkto(v)
                else
                        res.new_field("wat?").append(mproperty.name)
                end

                if is_intro then
                else
                        res.new_field("intro").add mproperty.intro.linkto_text(v, "in {mproperty.intro.mclassdef}")
                end
                add_doc_to_infobox(res)
                if mproperty.mpropdefs.length > 1 then
                        var c = res.new_dropdown("redef", "redefinitions")
                        for x in mproperty.mpropdefs do
                                c.open("li").add x.linkto_text(v, "in {x.mclassdef}")
                        end
                end

                return res
        end
end

redef class MClassType
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, to_s)
                res.href = v.hrefto(self)
                res.new_field("class").add mclass.intro.linkto(v)
                add_doc_to_infobox(res)
                return res
        end
        redef fun linkto(v)
        do
                return mclass.intro.linkto(v)
        end
end
redef class MVirtualType
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, to_s)
                res.href = v.hrefto(mproperty)
                var p = mproperty
                res.new_field("virtual type").add p.intro.linkto(v)
                add_doc_to_infobox(res)
                return res
        end
        redef fun linkto(v)
        do
                return mproperty.intro.linkto(v)
        end
end
redef class MParameterType
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, to_s)
                res.new_field("parameter type").append("{name} from class ").add mclass.intro.linkto(v)
                return res
        end
end

redef class MNullableType
        redef fun infobox(v)
        do
                return mtype.infobox(v)
        end
        redef fun linkto(v)
        do
                var res = new HTMLTag("span")
                res.append("nullable ").add(mtype.linkto(v))
                return res
        end
end

redef class MNotNullType
        redef fun infobox(v)
        do
                return mtype.infobox(v)
        end
        redef fun linkto(v)
        do
                var res = new HTMLTag("span")
                res.append("not null ").add(mtype.linkto(v))
                return res
        end
end

redef class MNullType
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, to_s)
                return res
        end
        redef fun linkto(v)
        do
                var res = new HTMLTag("span")
                res.append("null")
                return res
        end
end

redef class MSignature
        redef fun linkto(v)
        do
                var res = new HTMLTag("span")
                var first = true
                if not mparameters.is_empty then
                        res.append "("
                        for p in mparameters do
                                if first then
                                        first = false
                                else
                                        res.append ", "
                                end
                                res.append p.name
                                res.append ": "
                                res.add p.mtype.linkto(v)
                        end
                        res.append ")"
                end
                var ret = return_mtype
                if ret != null then
                        res.append ": "
                        res.add ret.linkto(v)
                end
                return res
        end
end

redef class CallSite
        redef fun infobox(v)
        do
                var res = new HInfoBox(v, "call {mpropdef}")
                res.href = v.hrefto(mpropdef)
                res.new_field("call").add(mpropdef.linkto(v)).add(msignature.linkto(v))
                if mpropdef.is_intro then
                else
                        res.new_field("intro").add mproperty.intro.linkto_text(v, "in {mproperty.intro.mclassdef}")
                end
                add_doc_to_infobox(res)

                return res
        end
        redef fun linkto(v)
        do
                return mpropdef.linkto(v)
        end
end

redef class Variable
        super HInfoBoxable
        redef fun infobox(v)
        do
                var declared_type = self.declared_type
                if declared_type == null then
                        var res = new HInfoBox(v, "{name}")
                        res.new_field("local var").append("{name}")
                        return res
                end
                var res = new HInfoBox(v, "{name}: {declared_type}")
                res.new_field("local var").append("{name}:").add(declared_type.linkto(v))
                return res
        end
end


##

redef class ANode
        # Optionally creates a tag that encapsulate the AST element on HTML rendering
        protected fun make_tag(v: HighlightVisitor): nullable HTMLTag do return null

        # Add aditionnal information on a child-token and return an additionnal HInfoBox on it
        protected fun decorate_tag(v: HighlightVisitor, res: HTMLTag, token: Token): nullable HInfoBox
        do
                #debug("no decoration for {token.inspect}")
                #res.add_class("nc_error")
                return null
        end

        # Return a optional infobox
        fun infobox(v: HighlightVisitor): nullable HInfoBox do return null
end

redef class AQclassid
        redef fun decorate_tag(v, res, token)
        do
                if token != n_id then return null
                var parent = self.parent
                if parent == null then return null
                return parent.decorate_tag(v, res, token)
        end
end

redef class AQid
        redef fun decorate_tag(v, res, token)
        do
                if token != n_id then return null
                var parent = self.parent
                if parent == null then return null
                return parent.decorate_tag(v, res, token)
        end
end

redef class AStdClassdef
        redef fun make_tag(v)
        do
                var res = new HTMLTag("span")
                res.add_class("nc_cdef")
                var md = mclassdef
                if md != null then res.attr("id", md.to_s)
                return res
        end
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TClassid then return null
                res.add_class("nc_def")

                var md = mclassdef
                if md == null then return null
                return md.infobox(v)
        end
end
redef class APropdef
        redef fun make_tag(v)
        do
                var res = new HTMLTag("span")
                res.add_class("nc_pdef")
                var mpd
                mpd = mpropdef
                if mpd != null then
                        #res.add(tag(mpd))
                        res.attr("id", mpd.to_s)
                end
                if self isa AAttrPropdef then
                        mpd = mreadpropdef
                        if mpd != null then res.add(tag(mpd))
                        mpd = mwritepropdef
                        if mpd != null then res.add(tag(mpd))
                end
                return res
        end

        private fun tag(mpd: MPropDef): HTMLTag
        do
                var a = new HTMLTag("a")
                a.attr("id", mpd.to_s)
                return a
        end
end

redef class Token
        # Produce an HTMLTag with the correct contents and CSS classes
        # Subclasses can redefine it to decorate the tag
        redef fun make_tag(v): HTMLTag
        do
                var res = new HTMLTag("span")
                res.text(text)
                return res
        end
end

redef class TokenKeyword
        redef fun make_tag(v)
        do
                var res = super
                res.add_class("nc_k")
                return res
        end
end
redef class TokenOperator
        redef fun make_tag(v)
        do
                var res = super
                res.add_class("nc_o")
                return res
        end
end

redef class AVarFormExpr
        redef fun decorate_tag(v, res, token)
        do
                if token != n_id then return null
                var variable = self.variable
                if variable == null then return null
                res.add_class("nc_v")
                return variable.infobox(v)
        end
end

redef class AVardeclExpr
        redef fun decorate_tag(v, res, token)
        do
                if token != n_id then return null
                var variable = self.variable
                if variable == null then return null
                res.add_class("nc_v")
                return variable.infobox(v)
        end
end

redef class AForGroup
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TId then return null
                var vs = variables
                if vs == null then return null
                res.add_class("nc_v")
                var idx = n_ids.index_of(token)
                var variable = vs[idx]
                return variable.infobox(v)
        end
end

redef class AParam
        redef fun decorate_tag(v, res, token)
        do
                if token != n_id then return null
                var mp = mparameter
                if mp == null then return null
                var variable = self.variable
                if variable == null then return null
                res.add_class("nc_v")
                return variable.infobox(v)
        end
end

redef class AAssertExpr
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TId then return null
                res.add_class("nc_ast")
                return null
        end
end

redef class ALabel
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TId then return null
                res.add_class("nc_la")
                return null
        end
end

redef class ASendExpr
        redef fun decorate_tag(v, res, token)
        do
                var callsite = self.callsite
                if callsite == null then return null
                return callsite.infobox(v)
        end
end

redef class ANewExpr
        redef fun decorate_tag(v, res, token)
        do
                var callsite = self.callsite
                if callsite == null then return null
                return callsite.infobox(v)
        end
end

redef class AAssignOp
        redef fun decorate_tag(v, res, token)
        do
                var p = parent
                assert p isa AReassignFormExpr

                var callsite = p.reassign_callsite
                if callsite == null then return null
                return callsite.infobox(v)
        end
end

redef class AModuleName
        redef fun decorate_tag(v, res, token)
        do
                var p = parent
                if p == null then return null
                return p.decorate_tag(v, res, token)
        end
end

redef class AModuledecl
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TId then return null
                res.add_class("nc_def")
                res.add_class("nc_m")
                var p = parent
                assert p isa AModule
                var mm = p.mmodule
                if mm == null then return null
                return mm.infobox(v)
        end
end

redef class AStdImport
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TId then return null
                res.add_class("nc_m")
                var mm = mmodule
                if mm == null then return null
                return mm.infobox(v)
        end
end
redef class AAttrPropdef
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TId then return null
                res.add_class("nc_def")
                var mpd: nullable MPropDef
                mpd = mreadpropdef
                if mpd == null then mpd = mpropdef
                if mpd == null then return null
                return mpd.infobox(v)
        end
end

redef class TId
        redef fun make_tag(v)
        do
                var res = super
                res.add_class("nc_i")
                return res
        end
end
redef class AMethid
        redef fun make_tag(v)
        do
                var res = new HTMLTag("span")
                res.add_class("nc_def")
                return res
        end
        redef fun decorate_tag(v, res, token)
        do
                return null
                # nothing to decorate
        end
        redef fun infobox(v)
        do
                var p = parent
                if not p isa AMethPropdef then return null
                var mpd = p.mpropdef
                if mpd == null then return null
                return mpd.infobox(v)
        end
end
redef class TAttrid
        redef fun make_tag(v)
        do
                var res = super
                res.add_class("nc_a")
                return res
        end
end
redef class AAttrFormExpr
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TAttrid then return null
                var p = mproperty
                if p == null then return null
                return p.intro.infobox(v)
        end
end
redef class TClassid
        redef fun make_tag(v)
        do
                var res = super
                res.add_class("nc_t")
                return res
        end
end
redef class AType
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TClassid then return null
                var mt = mtype
                if mt == null then return null
                mt = mt.undecorate
                if mt isa MFormalType then
                        res.add_class("nc_vt")
                end
                return mt.infobox(v)
        end
end
redef class AFormaldef
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TClassid then return null
                res.add_class("nc_vt")
                var mtype = self.mtype
                if mtype == null then return null
                return mtype.infobox(v)
        end
end
redef class ATypePropdef
        redef fun decorate_tag(v, res, token)
        do
                if not token isa TClassid then return null
                res.add_class("nc_def")
                var md = mpropdef
                if md == null then return null
                return md.infobox(v)
        end
end
redef class TComment
        redef fun make_tag(v)
        do
                var res = super
                if is_loose then
                        res.add_class("nc_c")
                end
                return res
        end
end
redef class ADoc
        redef fun make_tag(v)
        do
                var res = new HTMLTag("span")
                res.add_class("nc_d")
                return res
        end
end
redef class TokenLiteral
        redef fun make_tag(v)
        do
                var res = super
                res.add_class("nc_l")
                return res
        end
end
redef class ASuperstringExpr
        redef fun make_tag(v)
        do
                var res = new HTMLTag("span")
                res.add_class("nc_ss")
                return res
        end
end
redef class AStringFormExpr
        redef fun decorate_tag(v, res, token)
        do
                # Workaround to tag strings
                res.classes.remove("nc_l")
                res.add_class("nc_s")
                return super
        end
end
redef class AExpr
        redef fun decorate_tag(v, res, token)
        do
                var t = mtype
                if t == null then return null
                return t.infobox(v)
        end
end