Moved to using an AST based approach. The AST construction is not very advanced yet, but no regressions have occured.

assert-gooder.lua

@@ -3,6 +3,71 @@ local lexer = require 'lua_lang'
 
 --------------------------------------------------------------------------------
 
+
+local function get_value_of_string (string_str)
+    if string_str:sub(1, 1) == '"' or string_str:sub(1, 1) == '\'' then
+        return string_str:sub(2, -2)
+    end
+    assert(false)
+end
+
+local CONSTANT_VALUE_TOKEN = {
+	NUMBER	= tonumber,
+	STRING	= get_value_of_string,
+	TRUE  	= function() return true 	end,
+	FALSE 	= function() return false	end,
+	NIL   	= function() return nil  	end
+}
+
+local VALUE_TOKEN = { IDENTIFIER = true }
+for k in pairs(CONSTANT_VALUE_TOKEN) do  VALUE_TOKEN[k] = true  end
+
+local COMPARE_BINOP = {
+	EQ  = true,
+	NEQ = true,
+	LEQ = true,
+	GEQ = true,
+	LE  = true,
+	GT  = true,
+}
+
+local function get_value_token (token)
+    if CONSTANT_VALUE_TOKEN[token.token]then
+        return { exp = token.token, value = CONSTANT_VALUE_TOKEN[token.token](token.text) }
+    elseif token.token == 'IDENTIFIER' then
+        return { exp = 'LVALUE', token.text }
+    end
+    assert(false)
+end
+
+local function parse (tokens)
+    -- TODO: Make a more general parser
+    assert(type(tokens) == 'table')
+    --
+
+    if #tokens == 6 and tokens[1].text == 'type' and tokens[2].token == 'LPAR' and tokens[3].token == 'IDENTIFIER' and tokens[4].token == 'RPAR'and tokens[5].token == 'EQ'and tokens[6].token == 'STRING' then
+        return {
+            exp   = 'COMPARE',
+            binop = 'EQ',
+            left  = { exp = 'CALL', callee = get_value_token(tokens[1]), get_value_token(tokens[3]) },
+            right = get_value_token(tokens[6]),
+        }
+    elseif #tokens == 3 and VALUE_TOKEN[tokens[1].token] and COMPARE_BINOP[tokens[2].token] and VALUE_TOKEN[tokens[3].token] then
+        return {
+            exp  	= 'COMPARE',
+            binop	= tokens[2].token,
+            left 	= get_value_token(tokens[1]),
+            right	= get_value_token(tokens[3])
+        }
+    elseif #tokens == 1 then
+        return get_value_token(tokens[1])
+    else
+        print(require'pretty'(tokens))
+        --assert(false)
+        return nil
+    end
+end
+
 local function get_assert_body_text (call_info)
 	if call_info.what == 'Lua' then
 		-- Find filetext
@@ -78,13 +143,6 @@ local function get_function_name (call_info)
 	return string.format('the anonymous function %s', where)
 end
 
-local function get_value_of_string (string_str)
-	if string_str:sub(1, 1) == '"' or string_str:sub(1, 1) == '\'' then
-		return string_str:sub(2, -2)
-	end
-	assert(false)
-end
-
 local function fmt_val (val)
 	if type(val) == 'string' then
 		return string.format('%q', val)
@@ -93,23 +151,21 @@ local function fmt_val (val)
 	end
 end
 
-local function get_variable_and_prefix (gotten_name, level)
+local function fmt_lvalue (lvalue)
-	assert(type(gotten_name) == 'string')
+    assert(type(lvalue) == 'table' and lvalue.exp == 'LVALUE')
-	assert(type(level) == 'number')
+    return table.concat(lvalue, '.')
-	--
-	local gotten_val, var_scope, in_func  =  get_variable(gotten_name, level + 1)
-	local func_name = in_func and (' to '..get_function_name(debug.getinfo(level + 1))) or ''
-	return gotten_val, ('assertion failed! bad %s \'%s\'%s'):format(var_scope, gotten_name, func_name)
 end
 
+local function get_variable_and_prefix (lvalue, level)
+	assert(type(lvalue) == 'table' and lvalue.exp == 'LVALUE')
+	assert(type(level) == 'number')
+	--
+	local base_value, var_scope, in_func  =  get_variable(lvalue[1], level + 1)
+    local value = base_value -- TODO: Generalize to any lvalue
+	local func_name = in_func and (' to '..get_function_name(debug.getinfo(level + 1))) or ''
+	return value, ('assertion failed! bad %s \'%s\'%s'):format(var_scope, fmt_lvalue(lvalue), func_name)
+end
 
-local CONSTANT_VALUE_TOKEN = {
-	NUMBER	= tonumber,
-	STRING	= get_value_of_string,
-	TRUE  	= function() return true 	end,
-	FALSE 	= function() return false	end,
-	NIL   	= function() return nil  	end
-}
 
 local PRIMITIVE_VALUES = {
 	['nil']    	= true,
@@ -122,11 +178,6 @@ local COMPLEX_TYPES = {
 	['cdata']   	= true,
 }
 
-local function get_value_of_const_token (token)
-	assert(CONSTANT_VALUE_TOKEN[token.token])
-	return CONSTANT_VALUE_TOKEN[token.token](token.text)
-end
-
 local function fmt_with_type (val)
 	-- Primitive values ARE their type, and don't need the annotation.
 	if PRIMITIVE_VALUES[type(val)] then  return tostring(val)  end
@@ -142,32 +193,35 @@ return function (condition)
 	if condition then  return  condition  end
 	local call_info = debug.getinfo(2)
 	local tokens, body_text = get_assert_body(call_info)
+	local ast = parse(tokens)
 
-	if #tokens == 6 and tokens[1].text == 'type' and tokens[2].token == 'LPAR' and tokens[3].token == 'IDENTIFIER' and tokens[4].token == 'RPAR'and tokens[5].token == 'EQ'and tokens[6].token == 'STRING' then
+    if ast == nil then
-		local gotten_val, prefix  =  get_variable_and_prefix(tokens[3].text, 2)
+        error(('assertion failed! expression `%s` evaluated to %s'):format(body_text, condition), 2)
-		error(('%s (%s expected, but got %s: %s)'):format(prefix, get_value_of_string(tokens[6].text), type(gotten_val), fmt_val(gotten_val)), 2)
-	elseif #tokens == 3 and tokens[1].token == 'IDENTIFIER' and tokens[2].token == 'EQ' and CONSTANT_VALUE_TOKEN[tokens[3].token] then
-		local gotten_val, prefix  =  get_variable_and_prefix(tokens[1].text, 2)
 
-		local expected_value = get_value_of_const_token(tokens[3])
+	elseif ast.exp == 'COMPARE' and ast.binop == 'EQ' and ast.left.exp == 'CALL' and ast.left.callee.exp == 'LVALUE' and ast.left.callee[1] == 'type' then
-		local type_annotation = (type(expected_value) == type(gotten_val)) and '' or (' '..type(gotten_val))
+		local gotten_val, prefix  =  get_variable_and_prefix(ast.left[1], 2)
+		error(('%s (%s expected, but got %s: %s)'):format(prefix, ast.right.value, type(gotten_val), fmt_val(gotten_val)), 2)
 
-		error(('%s (%s expected, but got%s: %s)'):format(prefix, fmt_with_type(expected_value), type_annotation, fmt_val(gotten_val)), 2)
+	elseif ast.exp == 'COMPARE' and ast.binop == 'EQ' then
-	elseif #tokens == 3 and tokens[1].token == 'IDENTIFIER' and tokens[2].token == 'NEQ' and CONSTANT_VALUE_TOKEN[tokens[3].token] then
+		local gotten_value, prefix  =  get_variable_and_prefix(ast.left, 2)
-		local gotten_val, prefix  =  get_variable_and_prefix(tokens[1].text, 2)
+		local expected_value  = ast.right.value
-
+		local type_annotation = (type(expected_value) == type(gotten_value)) and '' or (' '..type(gotten_value))
-		local expected_value = get_value_of_const_token(tokens[3])
+		error(('%s (%s expected, but got%s: %s)'):format(prefix, fmt_with_type(expected_value), type_annotation, fmt_val(gotten_value)), 2)
 
+	elseif ast.exp == 'COMPARE' and ast.binop == 'NEQ' then
+		local gotten_val, prefix  =  get_variable_and_prefix(ast.left, 2)
+		local expected_value = ast.right.value
 		error(('%s (expected anything other than %s, but got %s)'):format(prefix, fmt_with_type(expected_value), fmt_val(gotten_val)), 2)
-	elseif #tokens == 1 and tokens[1].token == 'IDENTIFIER' then
+
-		local gotten_val, prefix  =  get_variable_and_prefix(tokens[1].text, 2)
+	elseif ast.exp == 'LVALUE' then
+		local gotten_val, prefix  =  get_variable_and_prefix(ast, 2)
 		error(('%s (truthy expected, but got %s)'):format(prefix, fmt_val(gotten_val)), 2)
-	elseif #tokens == 1 and (tokens[1].token == 'NIL' or tokens[1].token == 'FALSE') then
+
+    elseif CONSTANT_VALUE_TOKEN[ast.exp] then
 		local func_name  =  get_function_name(call_info)
 		error(('assertion failed! this assert will always fail, as it\'s body is `%s`. assumingly this should be an unreachable part of %s'):format(body_text, func_name), 2)
-	elseif #tokens == 1 then
+
-		error 'should be unreachable!'
     else
-		error(('assertion failed! expression `%s` evaluated to %s'):format(body_text, condition), 2)
+        error(('[assert-gooder/internal]: Unknown expression type %s'):format(ast.exp))
     end
 end

test/test_assert-gooder.lua

@@ -47,6 +47,31 @@ SUITE:addTest('argument to named function', function ()
 	assert_equal('./test/test_assert-gooder.lua:'..curline(-3)..': '..'assertion failed! bad argument #1 \'a\' to \'f\' (string expected, but got number: 2)', msg)
 end)
 
+
+SUITE:addTest('indexing', function ()
+	local _, msg  =  pcall(function ()
+		local a = { b = 39 }
+		assert(type(a.b) == 'string')
+	end)
+	assert_equal('./test/test_assert-gooder.lua:'..curline(-2)..': '..'assertion failed! bad key "b" in local \'a\' (string expected, but got number: 39)', msg)
+end)
+
+SUITE:addTest('subscript constant', function ()
+	local _, msg  =  pcall(function ()
+		local a = { 4, 2, 3, 6 }
+		assert(type(a.b) == 'string')
+	end)
+	assert_equal('./test/test_assert-gooder.lua:'..curline(-2)..': '..'assertion failed! bad key 2 in local \'a\' (string expected, but got number: 2)', msg)
+end)
+
+SUITE:addTest('subscript variable', function ()
+	local _, msg  =  pcall(function ()
+		local a, i = { 4, 2, 3, 6 }, 2
+		assert(type(a.b) == 'string')
+	end)
+	assert_equal('./test/test_assert-gooder.lua:'..curline(-2)..': '..'assertion failed! bad key 2 in local \'a\' (string expected, but got number: 2)', msg)
+end)
+
 --------------------------------------------------------------------------------
 
 SUITE:addTest('can improve asserts in loaded strings too', function ()
@@ -98,6 +123,15 @@ SUITE:addTest('truthy', function ()
 	assert_equal('./test/test_assert-gooder.lua:'..curline(-2)..': '..'assertion failed! bad local \'a\' (truthy expected, but got false)', msg)
 end)
 
+SUITE:addTest('truthy indexing', function ()
+	local _, msg  =  pcall(function ()
+		local a = { b = false }
+		assert(a.b)
+	end)
+	assert_equal('./test/test_assert-gooder.lua:'..curline(-2)..': '..'assertion failed! bad key "b" in local \'a\' (truthy expected, but got false)', msg)
+end)
+
+
 SUITE:addTest('not equal', function (constant_value, msg_in_pars)
 	local func = loadstring (("return function()                            local a = %s; assert(a ~= %s)  end"):format(constant_value, constant_value)) ()
 	local _, msg = pcall(setfenv(func, getfenv()))
@@ -124,8 +158,6 @@ SUITE:addTest('constant nil', function ()
 	assert_equal('./test/test_assert-gooder.lua:'..curline(-2)..': '..'assertion failed! this assert will always fail, as it\'s body is `nil`. assumingly this should be an unreachable part of the anonymous function at ./test/test_assert-gooder.lua:'..curline(-3), msg)
 end)
 
-
-
 --------------------------------------------------------------------------------
 
 return SUITE