diff --git a/build/cyan/colorstring.lua b/build/cyan/colorstring.lua
index 7f4f8f0..23ec21e 100644
--- a/build/cyan/colorstring.lua
+++ b/build/cyan/colorstring.lua
@@ -29,7 +29,7 @@ local ColorString = {}
 
 function ColorString:len()
    local l = 0
-   for _, chunk in ipairs(self.content) do
+   for chunk in ivalues(self.content) do
       if type(chunk) == "string" then
          l = l + #chunk
       end
@@ -39,7 +39,7 @@ end
 
 local function append(base, other)
    if type(other) == "table" then
-      for _, chunk in ipairs(other.content) do
+      for chunk in ivalues(other.content) do
          table.insert(base.content, chunk)
       end
    else
@@ -72,9 +72,8 @@ function ColorString:tostring()
    return table.concat(map(self.content, function(chunk)
       if type(chunk) == "string" then
          return chunk
-      else
-         return ansi.CSI .. table.concat(map(chunk, tostring), ";") .. "m"
       end
+      return ansi.CSI .. table.concat(map(chunk, tostring), ";") .. "m"
    end))
 end
 
@@ -160,9 +159,8 @@ end
 function colorstring.copy(str)
    if type(str) == "string" then
       return str
-   else
-      return str:copy()
    end
+   return str:copy()
 end
 
 local cs = colorstring.colors
diff --git a/build/cyan/command.lua b/build/cyan/command.lua
index c615f04..401f1cc 100644
--- a/build/cyan/command.lua
+++ b/build/cyan/command.lua
@@ -1,4 +1,4 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local ipairs = _tl_compat and _tl_compat.ipairs or ipairs; local pairs = _tl_compat and _tl_compat.pairs or pairs
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local pairs = _tl_compat and _tl_compat.pairs or pairs
 
 
 
@@ -10,8 +10,8 @@ local fs = require("cyan.fs")
 local log = require("cyan.log")
 local util = require("cyan.util")
 
-local merge_list, sort, from, keys, contains =
-util.tab.merge_list, util.tab.sort_in_place, util.tab.from, util.tab.keys, util.tab.contains
+local merge_list, sort, from, keys, contains, ivalues =
+util.tab.merge_list, util.tab.sort_in_place, util.tab.from, util.tab.keys, util.tab.contains, util.tab.ivalues
 
 local Args = {}
 
@@ -76,7 +76,7 @@ function command.new(cmd)
 
    commands[cmd.name] = cmd
    if cmd.script_hooks then
-      for _, h in ipairs(cmd.script_hooks) do
+      for h in ivalues(cmd.script_hooks) do
          hooks[cmd.name .. ":" .. h] = true
       end
    end
diff --git a/build/cyan/commands/build.lua b/build/cyan/commands/build.lua
index e701b0a..edb9ee0 100644
--- a/build/cyan/commands/build.lua
+++ b/build/cyan/commands/build.lua
@@ -1,4 +1,4 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local coroutine = _tl_compat and _tl_compat.coroutine or coroutine; local io = _tl_compat and _tl_compat.io or io; local ipairs = _tl_compat and _tl_compat.ipairs or ipairs; local os = _tl_compat and _tl_compat.os or os; local pairs = _tl_compat and _tl_compat.pairs or pairs; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table; local _tl_table_unpack = unpack or table.unpack
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local coroutine = _tl_compat and _tl_compat.coroutine or coroutine; local io = _tl_compat and _tl_compat.io or io; local os = _tl_compat and _tl_compat.os or os; local pairs = _tl_compat and _tl_compat.pairs or pairs; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table; local _tl_table_unpack = unpack or table.unpack
 
 local argparse = require("argparse")
 local tl = require("tl")
@@ -19,7 +19,8 @@ local function exists_and_is_dir(prefix, p)
    if not p:exists() then
       log.err(string.format("%s %q does not exist", prefix, p:to_real_path()))
       return false
-   elseif not p:is_directory() then
+   end
+   if not p:is_directory() then
       log.err(string.format("%s %q is not a directory", prefix, p:to_real_path()))
       return false
    end
@@ -283,19 +284,19 @@ local function build(args, loaded_config, starting_dir)
                   log.err("Unable to prune ", kind, " '", disp, "': ", err)
                end
             end
-            for _, p in ipairs(unexpected_files) do
+            for p in ivalues(unexpected_files) do
                prune(p, "file")
             end
-            for _, p in ipairs(unexpected_directories) do
+            for p in ivalues(unexpected_directories) do
                prune(p, "directory")
             end
          else
             local strs = {}
-            for _, p in ipairs(unexpected_files) do
+            for p in ivalues(unexpected_files) do
                table.insert(strs, "\n   ")
                table.insert(strs, display_filename(p))
             end
-            for _, p in ipairs(unexpected_directories) do
+            for p in ivalues(unexpected_directories) do
                table.insert(strs, "\n   ")
                table.insert(strs, display_filename(p, true))
             end
diff --git a/build/cyan/commands/check-gen.lua b/build/cyan/commands/check-gen.lua
index 3ec0f75..fc8efc2 100644
--- a/build/cyan/commands/check-gen.lua
+++ b/build/cyan/commands/check-gen.lua
@@ -1,4 +1,4 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local io = _tl_compat and _tl_compat.io or io; local ipairs = _tl_compat and _tl_compat.ipairs or ipairs; local table = _tl_compat and _tl_compat.table or table
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local io = _tl_compat and _tl_compat.io or io; local table = _tl_compat and _tl_compat.table or table
 
 
 
@@ -13,7 +13,8 @@ local log = require("cyan.log")
 local fs = require("cyan.fs")
 local util = require("cyan.util")
 
-local map_ipairs = util.tab.map_ipairs
+local map_ipairs, ivalues =
+util.tab.map_ipairs, util.tab.ivalues
 
 local function command_exec(should_compile)
    return function(args, loaded_config, starting_dir)
@@ -120,7 +121,7 @@ local function command_exec(should_compile)
       if should_compile then
          if exit ~= 0 then return exit end
 
-         for _, data in ipairs(to_write) do
+         for data in ivalues(to_write) do
             local fh, err = io.open(data.outfile:to_real_path(), "w")
             if fh then
                local generated, gen_err = common.compile_ast(data.output_ast, loaded_config.gen_target)
diff --git a/build/cyan/commands/initialize.lua b/build/cyan/commands/initialize.lua
index bbcdbef..73e662a 100644
--- a/build/cyan/commands/initialize.lua
+++ b/build/cyan/commands/initialize.lua
@@ -1,4 +1,4 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local io = _tl_compat and _tl_compat.io or io; local ipairs = _tl_compat and _tl_compat.ipairs or ipairs; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local io = _tl_compat and _tl_compat.io or io; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table
 
 
 
@@ -9,6 +9,9 @@ local config = require("cyan.config")
 local cs = require("cyan.colorstring")
 local fs = require("cyan.fs")
 local log = require("cyan.log")
+local util = require("cyan.util")
+
+local ivalues = util.tab.ivalues
 
 local function exec(args, loaded_config, starting_dir)
    if not args.force and loaded_config.loaded_from then
@@ -43,15 +46,14 @@ local function exec(args, loaded_config, starting_dir)
          if ok then
             log.info("Created directory ", cs.highlight(cs.colors.file, p:to_real_path()))
             return true
-         else
-            log.err("Unable to create directory ", cs.highlight(cs.colors.file, p:to_real_path()), ":\n   ", err)
-            return false
          end
+         log.err("Unable to create directory ", cs.highlight(cs.colors.file, p:to_real_path()), ":\n   ", err)
+         return false
       end
       return true
    end
 
-   for _, p in ipairs({ directory, directory .. source, directory .. build }) do
+   for p in ivalues({ directory, directory .. source, directory .. build }) do
       if not try_mkdir(p) then
          return 1
       end
@@ -71,7 +73,7 @@ local function exec(args, loaded_config, starting_dir)
          return
       end
       ins(1, "%s = {\n", name)
-      for _, entry in ipairs(arr) do
+      for entry in ivalues(arr) do
          ins(2, "%q,\n", entry)
       end
       ins(1, "},\n", name)
diff --git a/build/cyan/commands/run.lua b/build/cyan/commands/run.lua
index 956eb70..ce82874 100644
--- a/build/cyan/commands/run.lua
+++ b/build/cyan/commands/run.lua
@@ -74,10 +74,9 @@ local function run(args, loaded_config, starting_dir)
    local ok, err = box:run(1000000000)
    if ok then
       return 0
-   else
-      log.err("Error in script:\n", err)
-      return 1
    end
+   log.err("Error in script:\n", err)
+   return 1
 end
 
 command.new({
diff --git a/build/cyan/config.lua b/build/cyan/config.lua
index a180b22..c442224 100644
--- a/build/cyan/config.lua
+++ b/build/cyan/config.lua
@@ -1,4 +1,4 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local ipairs = _tl_compat and _tl_compat.ipairs or ipairs; local pairs = _tl_compat and _tl_compat.pairs or pairs; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local pairs = _tl_compat and _tl_compat.pairs or pairs; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table
 
 
 
@@ -8,8 +8,8 @@ local fs = require("cyan.fs")
 local sandbox = require("cyan.sandbox")
 local util = require("cyan.util")
 
-local keys, sort, from, values =
-util.tab.keys, util.tab.sort_in_place, util.tab.from, util.tab.values
+local keys, sort, from, values, ivalues =
+util.tab.keys, util.tab.sort_in_place, util.tab.from, util.tab.values, util.tab.ivalues
 
 
 
@@ -53,7 +53,7 @@ local config = {
 local function get_types_in_array(val, typefn)
    typefn = typefn or type
    local set = {}
-   for _, v in ipairs(val) do
+   for v in ivalues(val) do
       set[typefn(v)] = true
    end
    return sort(from(keys(set)))
@@ -193,7 +193,7 @@ function config.is_config(c)
    local function verify_warnings(key)
       local arr = (c)[key]
       if arr then
-         for _, warning in ipairs(arr) do
+         for warning in ivalues(arr) do
             if not tl.warning_kinds[warning] then
                table.insert(errs, string.format("Unknown warning in %s: %q", key, warning))
             end
@@ -205,9 +205,9 @@ function config.is_config(c)
 
    if #errs > 0 then
       return nil, errs, warnings
-   else
-      return c, nil, warnings
    end
+
+   return c, nil, warnings
 end
 
 
diff --git a/build/cyan/fs/path.lua b/build/cyan/fs/path.lua
index e2e3c2e..66268ab 100644
--- a/build/cyan/fs/path.lua
+++ b/build/cyan/fs/path.lua
@@ -44,7 +44,8 @@ local function parse_string_path(s, use_os_sep)
    s = s:gsub(sep .. "+", sep)
    if s == "" then
       return {}
-   elseif s:sub(-1) == sep then
+   end
+   if s:sub(-1) == sep then
       s = s:sub(1, -2)
    end
 
@@ -84,15 +85,15 @@ end
 function path.ensure(s, use_os_sep)
    if type(s) == "string" then
       return path.new(s, use_os_sep)
-   else
-      return s
    end
+   return s
 end
 
 local function string_is_absolute_path(p)
    if path.separator == "/" then
       return p:sub(1, 1) == "/"
-   elseif path.separator == "\\" then
+   end
+   if path.separator == "\\" then
       return p:match("^%a:$")
    end
 end
@@ -143,9 +144,11 @@ function Path:is_absolute()
    if #self < 1 then return false end
    if path.separator == "/" then
       return self[1] == ""
-   elseif path.separator == "\\" then
+   end
+   if path.separator == "\\" then
       return self[1]:match("^%a:$")
    end
+   return false
 end
 
 
@@ -287,9 +290,8 @@ function Path:mkdir()
    local succ, err = self:mk_parent_dirs()
    if succ then
       return lfs.mkdir(self:to_real_path())
-   else
-      return false, err
    end
+   return false, err
 end
 
 
diff --git a/build/cyan/graph.lua b/build/cyan/graph.lua
index 51288d8..b4b68c0 100644
--- a/build/cyan/graph.lua
+++ b/build/cyan/graph.lua
@@ -239,9 +239,8 @@ function Dag:insert_file(fstr, in_dir)
    local cycles = check_for_cycles(self)
    if cycles then
       return false, cycles
-   else
-      return true
    end
+   return true
 end
 
 
@@ -271,9 +270,8 @@ function graph.scan_dir(dir, include, exclude)
    local cycles = check_for_cycles(d)
    if cycles then
       return nil, cycles
-   else
-      return d
    end
+   return d
 end
 
 return graph
diff --git a/build/cyan/interaction.lua b/build/cyan/interaction.lua
index a20129b..ef1e92c 100644
--- a/build/cyan/interaction.lua
+++ b/build/cyan/interaction.lua
@@ -1,9 +1,12 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local io = _tl_compat and _tl_compat.io or io; local ipairs = _tl_compat and _tl_compat.ipairs or ipairs; local string = _tl_compat and _tl_compat.string or string
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local io = _tl_compat and _tl_compat.io or io; local string = _tl_compat and _tl_compat.string or string
 
 
 local log = require("cyan.log")
 local cs = require("cyan.colorstring")
 local ansi = require("cyan.ansi")
+local util = require("cyan.util")
+
+local ivalues = util.tab.ivalues
 
 local interaction = {}
 
@@ -19,7 +22,7 @@ end
 
 local function to_string_set(list)
    local result = {}
-   for _, v in ipairs(list) do
+   for v in ivalues(list) do
       result[v:lower()] = true
    end
    return result
@@ -73,7 +76,8 @@ function interaction.yes_no_prompt(
 
       if affirm_set[input] then
          return true
-      elseif deny_set[input] then
+      end
+      if deny_set[input] then
          return false
       end
    end
diff --git a/build/cyan/log.lua b/build/cyan/log.lua
index 8a716a2..eae1d7f 100644
--- a/build/cyan/log.lua
+++ b/build/cyan/log.lua
@@ -83,9 +83,8 @@ do
       inspect = function(x)
          if type(x) == "string" then
             return x
-         else
-            return actual_inspect(x, inspect_opts)
          end
+         return actual_inspect(x, inspect_opts)
       end
    else
       inspect = tostring
diff --git a/build/cyan/sandbox.lua b/build/cyan/sandbox.lua
index b75a693..72fbc89 100644
--- a/build/cyan/sandbox.lua
+++ b/build/cyan/sandbox.lua
@@ -39,9 +39,9 @@ function Sandbox:run(max_instructions, ...)
       table.remove(res, 1)
       self._result = res
       return true
-   else
-      return false, res[2] .. "\n" .. debug.traceback(t)
    end
+
+   return false, res[2] .. "\n" .. debug.traceback(t)
 end
 
 function Sandbox:result()
diff --git a/build/cyan/tlcommon.lua b/build/cyan/tlcommon.lua
index e43607b..a30b8a1 100644
--- a/build/cyan/tlcommon.lua
+++ b/build/cyan/tlcommon.lua
@@ -1,4 +1,4 @@
-local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local ipairs = _tl_compat and _tl_compat.ipairs or ipairs; local load = _tl_compat and _tl_compat.load or load; local package = _tl_compat and _tl_compat.package or package; local pairs = _tl_compat and _tl_compat.pairs or pairs; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table; local _tl_table_unpack = unpack or table.unpack
+local _tl_compat; if (tonumber((_VERSION or ''):match('[%d.]*$')) or 0) < 5.3 then local p, m = true, require('compat53.module'); if p then _tl_compat = m end end; local load = _tl_compat and _tl_compat.load or load; local package = _tl_compat and _tl_compat.package or package; local pairs = _tl_compat and _tl_compat.pairs or pairs; local string = _tl_compat and _tl_compat.string or string; local table = _tl_compat and _tl_compat.table or table; local _tl_table_unpack = unpack or table.unpack
 
 
 
@@ -162,7 +162,8 @@ local highlights_by_content = {
 local function highlight_token(tk)
    if highlights_by_content[tk.tk] then
       return cs.highlight(highlights_by_content[tk.tk], tk.tk)
-   elseif highlights_by_kind[tk.kind] then
+   end
+   if highlights_by_kind[tk.kind] then
       return cs.highlight(highlights_by_kind[tk.kind], tk.tk)
    end
    return cs.new(tk.tk == "$EOF$" and "" or tk.tk)
@@ -179,7 +180,7 @@ function common.syntax_highlight(s)
    local tks = tl.lex(s)
    local highlighted = cs.new()
    local last_x = 1
-   for _, tk in ipairs(tks) do
+   for tk in ivalues(tks) do
 
       local ts = count_tabs(s:sub(last_x, tk.x - 1))
       if ts > 0 then
@@ -283,9 +284,8 @@ function common.report_result(r, c)
       if arr and #arr > 0 then
          common.report_errors(logger, arr, r.filename, category)
          return false
-      else
-         return true
       end
+      return true
    end
 
    report(log.warn, warnings, "warning")
diff --git a/build/cyan/util.lua b/build/cyan/util.lua
index 950b936..87c7552 100644
--- a/build/cyan/util.lua
+++ b/build/cyan/util.lua
@@ -59,7 +59,7 @@ end
 
 function tab.set(lst)
    local s = {}
-   for _, v in ipairs(lst) do
+   for v in tab.ivalues(lst) do
       s[v] = true
    end
    return s
@@ -81,11 +81,8 @@ function tab.map_ipairs(t, fn)
    local i = 0
    return function()
       i = i + 1
-      if not t[i] then
-         return
-      else
-         return i, fn(t[i])
-      end
+      if not t[i] then return end
+      return i, fn(t[i])
    end
 end
 
@@ -109,7 +106,7 @@ end
 function tab.filter(t, pred)
    local pass = {}
    local fail = {}
-   for _, v in ipairs(t) do
+   for v in tab.ivalues(t) do
       table.insert(pred(v) and pass or fail, v)
    end
    return pass, fail
@@ -121,10 +118,10 @@ function tab.merge_list(a, b)
    local new_list = {}
    a = a or {}
    b = b or {}
-   for _, v in ipairs(a) do
+   for v in tab.ivalues(a) do
       table.insert(new_list, v)
    end
-   for _, v in ipairs(b) do
+   for v in tab.ivalues(b) do
       table.insert(new_list, v)
    end
    return new_list
@@ -133,7 +130,7 @@ end
 
 
 function tab.contains(t, val)
-   for _, v in ipairs(t) do
+   for v in tab.ivalues(t) do
       if val == v then
          return true
       end
diff --git a/src/cyan/colorstring.tl b/src/cyan/colorstring.tl
index 3953023..f47bb4a 100644
--- a/src/cyan/colorstring.tl
+++ b/src/cyan/colorstring.tl
@@ -29,7 +29,7 @@ end
 --- Note that `ColorString:len() >= ColorString:tostring():len()`
 function ColorString:len(): integer
    local l = 0
-   for _, chunk in ipairs(self.content) do
+   for chunk in ivalues(self.content) do
       if chunk is string then
          l = l + #chunk
       end
@@ -39,7 +39,7 @@ end
 
 local function append(base: ColorString, other: string | ColorString)
    if other is ColorString then
-      for _, chunk in ipairs(other.content) do
+      for chunk in ivalues(other.content) do
          table.insert(base.content, chunk)
       end
    else
@@ -72,9 +72,8 @@ function ColorString:tostring(): string
    return table.concat(map(self.content, function(chunk: {integer} | string): string
       if chunk is string then
          return chunk
-      else
-         return ansi.CSI .. table.concat(map(chunk, tostring as function(integer): string), ";") .. "m"
       end
+      return ansi.CSI .. table.concat(map(chunk, tostring as function(integer): string), ";") .. "m"
    end))
 end
 
@@ -160,9 +159,8 @@ end
 function colorstring.copy(str: string | ColorString): string | ColorString
    if str is string then
       return str
-   else
-      return str:copy()
    end
+   return str:copy()
 end
 
 local cs <const> = colorstring.colors
diff --git a/src/cyan/command.tl b/src/cyan/command.tl
index a19f93f..21ad63e 100644
--- a/src/cyan/command.tl
+++ b/src/cyan/command.tl
@@ -10,8 +10,8 @@ local fs <const> = require("cyan.fs")
 local log <const> = require("cyan.log")
 local util <const> = require("cyan.util")
 
-local merge_list <const>, sort <const>, from <const>, keys <const>, contains <const>
-   = util.tab.merge_list, util.tab.sort_in_place, util.tab.from, util.tab.keys, util.tab.contains
+local merge_list <const>, sort <const>, from <const>, keys <const>, contains <const>, ivalues <const>
+   = util.tab.merge_list, util.tab.sort_in_place, util.tab.from, util.tab.keys, util.tab.contains, util.tab.ivalues
 
 local record Args
    command: string
@@ -76,7 +76,7 @@ function command.new(cmd: Command)
 
    commands[cmd.name] = cmd
    if cmd.script_hooks then
-      for _, h in ipairs(cmd.script_hooks) do
+      for h in ivalues(cmd.script_hooks) do
          hooks[cmd.name .. ":" .. h] = true
       end
    end
diff --git a/src/cyan/commands/build.tl b/src/cyan/commands/build.tl
index 1a1bd29..e783fc5 100644
--- a/src/cyan/commands/build.tl
+++ b/src/cyan/commands/build.tl
@@ -19,7 +19,8 @@ local function exists_and_is_dir(prefix: string, p: fs.Path): boolean
    if not p:exists() then
       log.err(string.format("%s %q does not exist", prefix, p:to_real_path()))
       return false
-   elseif not p:is_directory() then
+   end
+   if not p:is_directory() then
       log.err(string.format("%s %q is not a directory", prefix, p:to_real_path()))
       return false
    end
@@ -283,19 +284,19 @@ local function build(args: command.Args, loaded_config: config.Config, starting_
                   log.err("Unable to prune ", kind, " '", disp, "': ", err)
                end
             end
-            for _, p in ipairs(unexpected_files) do
+            for p in ivalues(unexpected_files) do
                prune(p, "file")
             end
-            for _, p in ipairs(unexpected_directories) do
+            for p in ivalues(unexpected_directories) do
                prune(p, "directory")
             end
          else
             local strs <const>: {string | cs.ColorString} = {}
-            for _, p in ipairs(unexpected_files) do
+            for p in ivalues(unexpected_files) do
                table.insert(strs, "\n   ")
                table.insert(strs, display_filename(p))
             end
-            for _, p in ipairs(unexpected_directories) do
+            for p in ivalues(unexpected_directories) do
                table.insert(strs, "\n   ")
                table.insert(strs, display_filename(p, true))
             end
diff --git a/src/cyan/commands/check-gen.tl b/src/cyan/commands/check-gen.tl
index 118b24f..54176d9 100644
--- a/src/cyan/commands/check-gen.tl
+++ b/src/cyan/commands/check-gen.tl
@@ -13,7 +13,8 @@ local log <const> = require("cyan.log")
 local fs <const> = require("cyan.fs")
 local util <const> = require("cyan.util")
 
-local map_ipairs <const> = util.tab.map_ipairs
+local map_ipairs <const>, ivalues <const>
+   = util.tab.map_ipairs, util.tab.ivalues
 
 local function command_exec(should_compile: boolean): command.CommandFn
    return function(args: command.Args, loaded_config: config.Config, starting_dir: fs.Path): integer
@@ -120,7 +121,7 @@ local function command_exec(should_compile: boolean): command.CommandFn
       if should_compile then
          if exit ~= 0 then return exit end
 
-         for _, data in ipairs(to_write) do
+         for data in ivalues(to_write) do
             local fh <const>, err <const> = io.open(data.outfile:to_real_path(), "w")
             if fh then
                local generated <const>, gen_err <const> = common.compile_ast(data.output_ast, loaded_config.gen_target)
diff --git a/src/cyan/commands/initialize.tl b/src/cyan/commands/initialize.tl
index c812078..c13c581 100644
--- a/src/cyan/commands/initialize.tl
+++ b/src/cyan/commands/initialize.tl
@@ -9,6 +9,9 @@ local config <const> = require("cyan.config")
 local cs <const> = require("cyan.colorstring")
 local fs <const> = require("cyan.fs")
 local log <const> = require("cyan.log")
+local util <const> = require("cyan.util")
+
+local ivalues <const> = util.tab.ivalues
 
 local function exec(args: command.Args, loaded_config: config.Config, starting_dir: fs.Path): integer
    if not args.force and loaded_config.loaded_from then
@@ -43,15 +46,14 @@ local function exec(args: command.Args, loaded_config: config.Config, starting_d
          if ok then
             log.info("Created directory ", cs.highlight(cs.colors.file, p:to_real_path()))
             return true
-         else
-            log.err("Unable to create directory ", cs.highlight(cs.colors.file, p:to_real_path()), ":\n   ", err)
-            return false
          end
+         log.err("Unable to create directory ", cs.highlight(cs.colors.file, p:to_real_path()), ":\n   ", err)
+         return false
       end
       return true
    end
 
-   for _, p in ipairs{directory, directory .. source, directory .. build} do
+   for p in ivalues{directory, directory .. source, directory .. build} do
       if not try_mkdir(p) then
          return 1
       end
@@ -71,7 +73,7 @@ local function exec(args: command.Args, loaded_config: config.Config, starting_d
          return
       end
       ins(1, "%s = {\n", name)
-      for _, entry in ipairs(arr) do
+      for entry in ivalues(arr) do
          ins(2, "%q,\n", entry)
       end
       ins(1, "},\n", name)
diff --git a/src/cyan/commands/run.tl b/src/cyan/commands/run.tl
index e2e61c3..d35a5b6 100644
--- a/src/cyan/commands/run.tl
+++ b/src/cyan/commands/run.tl
@@ -74,10 +74,9 @@ local function run(args: command.Args, loaded_config: config.Config, starting_di
    local ok <const>, err <const> = box:run(1000000000)
    if ok then
       return 0
-   else
-      log.err("Error in script:\n", err)
-      return 1
    end
+   log.err("Error in script:\n", err)
+   return 1
 end
 
 command.new{
diff --git a/src/cyan/config.tl b/src/cyan/config.tl
index e41d912..417ac8c 100644
--- a/src/cyan/config.tl
+++ b/src/cyan/config.tl
@@ -8,8 +8,8 @@ local fs <const> = require("cyan.fs")
 local sandbox <const> = require("cyan.sandbox")
 local util <const> = require("cyan.util")
 
-local keys <const>, sort <const>, from <const>, values <const>
-   = util.tab.keys, util.tab.sort_in_place, util.tab.from, util.tab.values
+local keys <const>, sort <const>, from <const>, values <const>, ivalues <const>
+   = util.tab.keys, util.tab.sort_in_place, util.tab.from, util.tab.values, util.tab.ivalues
 
 ---@desc
 --- The config data
@@ -53,7 +53,7 @@ local config <const> = {
 local function get_types_in_array(val: {any}, typefn: function(any): string): {string}
    typefn = typefn or type
    local set <const> = {}
-   for _, v in ipairs(val) do
+   for v in ivalues(val) do
       set[typefn(v)] = true
    end
    return sort(from(keys(set)))
@@ -193,7 +193,7 @@ function config.is_config(c: any): Config, {string}, {string}
    local function verify_warnings(key: string)
       local arr <const> = (c as {string:{string}})[key]
       if arr then
-         for _, warning in ipairs(arr) do
+         for warning in ivalues(arr) do
             if not tl.warning_kinds[warning as tl.WarningKind] then
                table.insert(errs, string.format("Unknown warning in %s: %q", key, warning))
             end
@@ -205,9 +205,9 @@ function config.is_config(c: any): Config, {string}, {string}
 
    if #errs > 0 then
       return nil, errs, warnings
-   else
-      return c as Config, nil, warnings
    end
+
+   return c as Config, nil, warnings
 end
 
 ---@desc
diff --git a/src/cyan/fs/path.tl b/src/cyan/fs/path.tl
index 7a76f56..ffda156 100644
--- a/src/cyan/fs/path.tl
+++ b/src/cyan/fs/path.tl
@@ -44,7 +44,8 @@ local function parse_string_path(s: string, use_os_sep: boolean): {string}
    s = s:gsub(sep .. "+", sep)
    if s == "" then
       return {}
-   elseif s:sub(-1) == sep then
+   end
+   if s:sub(-1) == sep then
       s = s:sub(1, -2)
    end
 
@@ -84,15 +85,15 @@ end
 function path.ensure(s: string | Path, use_os_sep: boolean): Path
    if s is string then
       return path.new(s, use_os_sep)
-   else
-      return s
    end
+   return s
 end
 
 local function string_is_absolute_path(p: string): boolean
    if path.separator == "/" then
       return p:sub(1, 1) == "/"
-   elseif path.separator == "\\" then
+   end
+   if path.separator == "\\" then
       return p:match("^%a:$") as boolean
    end
 end
@@ -143,9 +144,11 @@ function Path:is_absolute(): boolean
    if #self < 1 then return false end
    if path.separator == "/" then
       return self[1] == ""
-   elseif path.separator == "\\" then
+   end
+   if path.separator == "\\" then
       return self[1]:match("^%a:$") as boolean
    end
+   return false
 end
 
 ---@desc
@@ -287,9 +290,8 @@ function Path:mkdir(): boolean, string
    local succ <const>, err <const> = self:mk_parent_dirs()
    if succ then
       return lfs.mkdir(self:to_real_path())
-   else
-      return false, err
    end
+   return false, err
 end
 
 ---@desc
diff --git a/src/cyan/graph.tl b/src/cyan/graph.tl
index 6c6f0e7..320f8f7 100644
--- a/src/cyan/graph.tl
+++ b/src/cyan/graph.tl
@@ -239,9 +239,8 @@ function Dag:insert_file(fstr: string | fs.Path, in_dir: string | fs.Path): bool
    local cycles <const> = check_for_cycles(self)
    if cycles then
       return false, cycles
-   else
-      return true
    end
+   return true
 end
 
 ---@desc
@@ -271,9 +270,8 @@ function graph.scan_dir(dir: string | fs.Path, include: {string}, exclude: {stri
    local cycles <const> = check_for_cycles(d)
    if cycles then
       return nil, cycles
-   else
-      return d
    end
+   return d
 end
 
 return graph
diff --git a/src/cyan/interaction.tl b/src/cyan/interaction.tl
index ec9bbd1..41f7773 100644
--- a/src/cyan/interaction.tl
+++ b/src/cyan/interaction.tl
@@ -4,6 +4,9 @@
 local log <const> = require("cyan.log")
 local cs <const> = require("cyan.colorstring")
 local ansi <const> = require("cyan.ansi")
+local util <const> = require("cyan.util")
+
+local ivalues <const> = util.tab.ivalues
 
 local interaction <const> = {}
 
@@ -19,7 +22,7 @@ end
 
 local function to_string_set(list: {string}): {string:boolean}
    local result <const> = {}
-   for _, v in ipairs(list) do
+   for v in ivalues(list) do
       result[v:lower()] = true
    end
    return result
@@ -73,7 +76,8 @@ function interaction.yes_no_prompt(
 
       if affirm_set[input] then
          return true
-      elseif deny_set[input] then
+      end
+      if deny_set[input] then
          return false
       end
    end
diff --git a/src/cyan/log.tl b/src/cyan/log.tl
index 2c8e297..6c1c935 100644
--- a/src/cyan/log.tl
+++ b/src/cyan/log.tl
@@ -83,9 +83,8 @@ do
       inspect = function(x: any): string
          if x is string then
             return x
-         else
-            return actual_inspect(x, inspect_opts)
          end
+         return actual_inspect(x, inspect_opts)
       end
    else
       inspect = tostring
diff --git a/src/cyan/sandbox.tl b/src/cyan/sandbox.tl
index c231d64..fd9e30c 100644
--- a/src/cyan/sandbox.tl
+++ b/src/cyan/sandbox.tl
@@ -39,9 +39,9 @@ function Sandbox:run(max_instructions: integer, ...: any): boolean, string
       table.remove(res, 1)
       self._result = res
       return true
-   else
-      return false, res[2] as string .. "\n" .. debug.traceback(t)
    end
+
+   return false, res[2] as string .. "\n" .. debug.traceback(t)
 end
 
 function Sandbox:result(): any...
diff --git a/src/cyan/tlcommon.tl b/src/cyan/tlcommon.tl
index 5563a8c..2b8b971 100644
--- a/src/cyan/tlcommon.tl
+++ b/src/cyan/tlcommon.tl
@@ -162,7 +162,8 @@ local highlights_by_content <const>: {string:{integer}} = {
 local function highlight_token(tk: Token): cs.ColorString
    if highlights_by_content[tk.tk] then
       return cs.highlight(highlights_by_content[tk.tk], tk.tk)
-   elseif highlights_by_kind[tk.kind] then
+   end
+   if highlights_by_kind[tk.kind] then
       return cs.highlight(highlights_by_kind[tk.kind], tk.tk)
    end
    return cs.new(tk.tk == "$EOF$" and "" or tk.tk)
@@ -179,7 +180,7 @@ function common.syntax_highlight(s: string): cs.ColorString
    local tks <const> = tl.lex(s) as {Token}
    local highlighted <const> = cs.new()
    local last_x = 1
-   for _, tk in ipairs(tks) do
+   for tk in ivalues(tks) do
       -- account for tabs
       local ts = count_tabs(s:sub(last_x, tk.x - 1))
       if ts > 0 then
@@ -283,9 +284,8 @@ function common.report_result(r: tl.Result, c: config.Config): boolean
       if arr and #arr > 0 then
          common.report_errors(logger, arr, r.filename, category)
          return false
-      else
-         return true
       end
+      return true
    end
 
    report(log.warn, warnings, "warning")
diff --git a/src/cyan/util.tl b/src/cyan/util.tl
index a98fbb7..e6f6e16 100644
--- a/src/cyan/util.tl
+++ b/src/cyan/util.tl
@@ -59,7 +59,7 @@ end
 --- Create a Set from a list
 function tab.set<Value>(lst: {Value}): {Value:boolean}
    local s <const> = {}
-   for _, v in ipairs(lst) do
+   for v in tab.ivalues(lst) do
       s[v] = true
    end
    return s
@@ -81,11 +81,8 @@ function tab.map_ipairs<Value, MappedValue>(t: {Value}, fn: function(Value): Map
    local i = 0
    return function(): integer, MappedValue
       i = i + 1
-      if not t[i] then
-         return
-      else
-         return i, fn(t[i])
-      end
+      if not t[i] then return end
+      return i, fn(t[i])
    end
 end
 
@@ -109,7 +106,7 @@ end
 function tab.filter<Value>(t: {Value}, pred: function(Value): boolean): {Value}, {Value}
    local pass <const>: {Value} = {}
    local fail <const>: {Value} = {}
-   for _, v in ipairs(t) do
+   for v in tab.ivalues(t) do
       table.insert(pred(v) and pass or fail, v)
    end
    return pass, fail
@@ -121,10 +118,10 @@ function tab.merge_list<Value>(a: {Value}, b: {Value}): {Value}
    local new_list <const> = {}
    a = a or {}
    b = b or {}
-   for _, v in ipairs(a) do
+   for v in tab.ivalues(a) do
       table.insert(new_list, v)
    end
-   for _, v in ipairs(b) do
+   for v in tab.ivalues(b) do
       table.insert(new_list, v)
    end
    return new_list
@@ -133,7 +130,7 @@ end
 ---@desc
 --- Report if an array contains an element (as determined by the `==` operator)
 function tab.contains<Value>(t: {Value}, val: Value): boolean
-   for _, v in ipairs(t) do
+   for v in tab.ivalues(t) do
       if val == v then
          return true
       end