lace.error.render: Report all lines that caused error

This makes use of the line information added to the error traces,
to report exactly which definitions also caused the problem.

3 files changed, 58 insertions, 19 deletions

diff --git a/lib/lace/error.lua b/lib/lace/error.lua
index cf21446..abbfa2f 100644
--- a/lib/lace/error.lua
+++ b/lib/lace/error.lua
@@ -103,28 +103,38 @@ local function _render(err)
    local ret = { err.msg }
 
    local wordset = {}
-   local function build_wordset(words, wordset)
+   local function build_wordset(words, wordset, parent_source, parent_linenr)
+      wordset.source = words.source or source
+      wordset.linenr = words.linenr or linenr
       for _, word in ipairs(words) do
          if type(word) ~= "table" then
             wordset[word] = true
          else
             local subwordset = {}
-            build_wordset(word.sub, subwordset)
+            build_wordset(word.sub, subwordset, wordset.source, wordset.linenr)
             wordset[word.nr] = subwordset
          end
       end
    end
    build_wordset(err.words, wordset)
 
-   -- The second is the source filename and line
-   ret[2] = err.words.source.source .. " :: " .. tostring(err.words.linenr)
-   -- The third line is the line of the input
-   local srcline = err.words.source.lines[err.words.linenr] or {
-      original = "???", content = { {spos = 1, epos = 3, str = "???"} }
-   }
-   ret[3] = srcline.original
+   local linelist = {}
+   local function build_linelist(wordset, parent_source, parent_linenr)
+      if parent_source ~= wordset.source or parent_linenr ~= wordset.linenr then
+         linelist[#linelist+1] = wordset
+      end
+      local srcline = wordset.source.lines[wordset.linenr] or {
+         original = "???", content = { {spos = 1, epos = 3, str = "???"} }
+      }
+      for w, info in ipairs(srcline.content) do
+         -- TODO: Sometimes wordset is table, but token has no subwords.
+         if type(wordset[w]) == "table" and info.sub then
+            build_linelist(wordset[w], wordset.source, wordset.linenr)
+         end
+      end
+   end
+   build_linelist(wordset)
 
-   -- The fourth line is the highlight for each word in question
    local function mark_my_words(line, wordset)
       local hlstr, cpos = "", 1
       for w, info in ipairs(line) do
@@ -133,12 +143,12 @@ local function _render(err)
             hlstr = hlstr .. " "
             cpos = cpos + 1
          end
-         -- TODO: The subword can be defined in a different line entirely,
-         --       at which point it's not a subword of word in this line.
-         --       This is the norm for explicit definitions.
-         --       Eventually we should trace back to the define's
-         --       definition and highlight where in that line the problem is.
-         if type(wordset[w]) == "table" and info.sub then
+         --  The subword can be defined in a different line entirely,
+         --  at which point it's not a subword of word in this line.
+         --  This is the norm for explicit definitions.
+         if info.sub and type(wordset[w]) == "table"
+         and wordset[w].source == wordset.source
+         and wordset[w].linenr == wordset.linenr then
             -- space for [
             hlstr, cpos = hlstr .. " ", cpos + 1
 
@@ -159,10 +169,18 @@ local function _render(err)
       end
       return hlstr, cpos
    end
-   local hlstr, _ = mark_my_words(srcline.content, wordset)
-   ret[4] = hlstr
 
-   -- The rendered error is those four strings joined by newlines
+   for _, wordset in ipairs(linelist) do
+      ret[#ret+1] = wordset.source.source .. " :: " .. tostring(wordset.linenr)
+      local srcline = wordset.source.lines[wordset.linenr] or {
+         original = "???", content = { {spos = 1, epos = 3, str = "???"} }
+      }
+      ret[#ret+1] = srcline.original
+      local hlstr, _ = mark_my_words(srcline.content, wordset)
+      ret[#ret+1] = hlstr
+   end
+
+   -- The rendered error is those strings joined by newlines
    return table.concat(ret, "\n")
 end
 
diff --git a/test/test-lace.engine-chaindefine-error.rules b/test/test-lace.engine-chaindefine-error.rules
new file mode 100644
index 0000000..1620172
--- /dev/null
+++ b/test/test-lace.engine-chaindefine-error.rules
@@ -0,0 +1,2 @@
+define bogus error
+allow "FAIL" [anyof [equal jeff banana] bogus]
diff --git a/test/test-lace.engine.lua b/test/test-lace.engine.lua
index 936a2ed..2e08bfc 100644
--- a/test/test-lace.engine.lua
+++ b/test/test-lace.engine.lua
@@ -289,6 +289,25 @@ function suite.subsubdefine_err_reported()
    assert(line4 == "                                         ^^^^^  ", "The fourth line highlights relevant words")
 end
 
+function suite.subdefine_chained_err_reported()
+   local ruleset, msg = lace.compiler.compile(comp_context, "chaindefine-error")
+   print""
+   --require 'pl.pretty'.dump(ruleset)
+   assert(type(ruleset) == "table", "Ruleset did not compile")
+   local ectx = {error = true}
+   local result, msg = lace.engine.run(ruleset, ectx)
+   assert(result == false, "Did not error out")
+   local lines = {}
+   msg:gsub("([^\n]*)\n?", function(c) table.insert(lines, c) end)
+   assert(lines[1] == "woah", "The first line must mention the error")
+   assert(lines[2] == "real-chaindefine-error :: 2", "The second line is where the error happened")
+   assert(lines[3] == 'allow "FAIL" [anyof [equal jeff banana] bogus]', "The third line is the original line")
+   assert(lines[4] == "                                        ^^^^^ ", "The fourth line highlights relevant words")
+   assert(lines[5] == "real-chaindefine-error :: 1", "The fifth line is where the definition that errored comes from")
+   assert(lines[6] == 'define bogus error', "The sixth line is the define")
+   assert(lines[7] == "             ^^^^^", "The seventh line highlights relevant words")
+end
+
 local count_ok = 0
 for _, testname in ipairs(testnames) do
 --   print("Run: " .. testname)