From 437b816f858e1bd4fc549d722903ae5407829bcd Mon Sep 17 00:00:00 2001
From: Connor Olding <cloningdonor@gmail.com>
Date: Sun, 27 Nov 2016 16:17:32 -0800
Subject: [PATCH] refactor label resolution into its own method

---
 lips/Preproc.lua | 85 +++++++++++++++++++++++-------------------------
 1 file changed, 41 insertions(+), 44 deletions(-)

diff --git a/lips/Preproc.lua b/lips/Preproc.lua
index a4a9137..89e136e 100644
--- a/lips/Preproc.lua
+++ b/lips/Preproc.lua
@@ -36,56 +36,55 @@ function Preproc:lookup(t)
         if t.tok == nil then
             self:error('undefined variable', name)
         end
-    elseif self.do_labels and t.tt == 'RELLABELSYM' or t.tt == 'RELLABEL' then
-        if t.tt == 'RELLABEL' then
-            t.tt = 'LABEL'
-            -- exploits the fact that user labels can't begin with a number
-            local name = t.tok:sub(2)
-            t.tok = tostring(self.i)..name
-        elseif t.tt == 'RELLABELSYM' then
-            local i = self.i
-            t.tt = 'LABELSYM'
+    end
+end
 
-            local rel = signs(t.tok)
-            assert(rel ~= 0, 'Internal Error: relative label without signs')
+function Preproc:resolve(t)
+    if t.tt == 'RELLABEL' then
+        t.tt = 'LABEL'
+        -- exploits the fact that user labels can't begin with a number
+        local name = t.tok:sub(2)
+        t.tok = tostring(self.i)..name
+    elseif t.tt == 'RELLABELSYM' then
+        local i = self.i
+        t.tt = 'LABELSYM'
 
-            local name = t.tok:sub(abs(rel) + 1)
-            local seen = 0
+        local rel = signs(t.tok)
+        assert(rel ~= 0, 'Internal Error: relative label without signs')
 
-            -- TODO: don't iterate over *every* label, just the ones nearby.
-            -- we could do this by popping labels as we pass over them.
-            -- (would need to iterate once forwards and once backwards
-            --  for plus and minus labels respectively)
-            if rel > 0 then
-                for _, rl in ipairs(self.plus_labels) do
-                    if rl.name == name and rl.index > i then
-                        seen = seen + 1
-                        if seen == rel then
-                            t.tok = tostring(rl.index)..name
-                            break
-                        end
-                    end
-                end
-            else
-                for _, rl in ipairs(self.minus_labels) do
-                    if rl.name == name and rl.index < i then
-                        seen = seen - 1
-                        if seen == rel then
-                            t.tok = tostring(rl.index)..name
-                            break
-                        end
+        local name = t.tok:sub(abs(rel) + 1)
+        local seen = 0
+
+        -- TODO: don't iterate over *every* label, just the ones nearby.
+        -- we could do this by popping labels as we pass over them.
+        -- (would need to iterate once forwards and once backwards
+        --  for plus and minus labels respectively)
+        if rel > 0 then
+            for _, rl in ipairs(self.plus_labels) do
+                if rl.name == name and rl.index > i then
+                    seen = seen + 1
+                    if seen == rel then
+                        t.tok = tostring(rl.index)..name
+                        break
                     end
                 end
             end
-
-            if seen ~= rel then
-                self:error('could not find appropriate relative label', t.tok)
+        else
+            for _, rl in ipairs(self.minus_labels) do
+                if rl.name == name and rl.index < i then
+                    seen = seen - 1
+                    if seen == rel then
+                        t.tok = tostring(rl.index)..name
+                        break
+                    end
+                end
             end
         end
-    else
-        return false
+
+        if seen ~= rel then
+            self:error('could not find appropriate relative label', t.tok)
+        end
     end
-    return true
 end
 
 function Preproc:check(s, i, tt)
@@ -115,7 +114,6 @@ function Preproc:process(statements)
     self.variables = {}
     self.plus_labels = {} -- constructed forwards
     self.minus_labels = {} -- constructed backwards
-    self.do_labels = false
 
     -- first pass: resolve variables and collect relative labels
     local new_statements = {}
@@ -152,10 +150,9 @@ function Preproc:process(statements)
     end
 
     -- second pass: resolve relative labels
-    self.do_labels = true
     for s in self:iter(new_statements) do
         for j, t in ipairs(s) do
-            self:lookup(t)
+            self:resolve(t)
         end
     end