Added macro 'luaL_pushfail'

The macro 'luaL_pushfail' documents all places in the standard libraries
that return nil to signal some kind of failure. It is defined as
'lua_pushnil'. The manual also got a notation (@fail) to document those
returns. The tests were changed to be agnostic regarding whether 'fail'
is 'nil' or 'false'.

testes/math.lua

@@ -39,7 +39,7 @@ do
 end
 
 assert(math.type(0) == "integer" and math.type(0.0) == "float"
-       and math.type("10") == nil)
+       and not math.type("10"))
 
 
 local function checkerror (msg, f, ...)
@@ -381,17 +381,17 @@ assert(tonumber(1/0) == 1/0)
 
 -- 'tonumber' with strings
 assert(tonumber("0") == 0)
-assert(tonumber("") == nil)
-assert(tonumber("  ") == nil)
-assert(tonumber("-") == nil)
-assert(tonumber("  -0x ") == nil)
-assert(tonumber{} == nil)
+assert(not tonumber(""))
+assert(not tonumber("  "))
+assert(not tonumber("-"))
+assert(not tonumber("  -0x "))
+assert(not tonumber{})
 assert(tonumber'+0.01' == 1/100 and tonumber'+.01' == 0.01 and
        tonumber'.01' == 0.01    and tonumber'-1.' == -1 and
        tonumber'+1.' == 1)
-assert(tonumber'+ 0.01' == nil and tonumber'+.e1' == nil and
-       tonumber'1e' == nil     and tonumber'1.0e+' == nil and
-       tonumber'.' == nil)
+assert(not tonumber'+ 0.01' and not tonumber'+.e1' and
+       not tonumber'1e'     and not tonumber'1.0e+' and
+       not tonumber'.')
 assert(tonumber('-012') == -010-2)
 assert(tonumber('-1.2e2') == - - -120)
 
@@ -445,45 +445,45 @@ local function f (...)
   end
 end
 
-assert(f(tonumber('fFfa', 15)) == nil)
-assert(f(tonumber('099', 8)) == nil)
-assert(f(tonumber('1\0', 2)) == nil)
-assert(f(tonumber('', 8)) == nil)
-assert(f(tonumber('  ', 9)) == nil)
-assert(f(tonumber('  ', 9)) == nil)
-assert(f(tonumber('0xf', 10)) == nil)
+assert(not f(tonumber('fFfa', 15)))
+assert(not f(tonumber('099', 8)))
+assert(not f(tonumber('1\0', 2)))
+assert(not f(tonumber('', 8)))
+assert(not f(tonumber('  ', 9)))
+assert(not f(tonumber('  ', 9)))
+assert(not f(tonumber('0xf', 10)))
 
-assert(f(tonumber('inf')) == nil)
-assert(f(tonumber(' INF ')) == nil)
-assert(f(tonumber('Nan')) == nil)
-assert(f(tonumber('nan')) == nil)
+assert(not f(tonumber('inf')))
+assert(not f(tonumber(' INF ')))
+assert(not f(tonumber('Nan')))
+assert(not f(tonumber('nan')))
 
-assert(f(tonumber('  ')) == nil)
-assert(f(tonumber('')) == nil)
-assert(f(tonumber('1  a')) == nil)
-assert(f(tonumber('1  a', 2)) == nil)
-assert(f(tonumber('1\0')) == nil)
-assert(f(tonumber('1 \0')) == nil)
-assert(f(tonumber('1\0 ')) == nil)
-assert(f(tonumber('e1')) == nil)
-assert(f(tonumber('e  1')) == nil)
-assert(f(tonumber(' 3.4.5 ')) == nil)
+assert(not f(tonumber('  ')))
+assert(not f(tonumber('')))
+assert(not f(tonumber('1  a')))
+assert(not f(tonumber('1  a', 2)))
+assert(not f(tonumber('1\0')))
+assert(not f(tonumber('1 \0')))
+assert(not f(tonumber('1\0 ')))
+assert(not f(tonumber('e1')))
+assert(not f(tonumber('e  1')))
+assert(not f(tonumber(' 3.4.5 ')))
 
 
 -- testing 'tonumber' for invalid hexadecimal formats
 
-assert(tonumber('0x') == nil)
-assert(tonumber('x') == nil)
-assert(tonumber('x3') == nil)
-assert(tonumber('0x3.3.3') == nil)   -- two decimal points
-assert(tonumber('00x2') == nil)
-assert(tonumber('0x 2') == nil)
-assert(tonumber('0 x2') == nil)
-assert(tonumber('23x') == nil)
-assert(tonumber('- 0xaa') == nil)
-assert(tonumber('-0xaaP ') == nil)   -- no exponent
-assert(tonumber('0x0.51p') == nil)
-assert(tonumber('0x5p+-2') == nil)
+assert(not tonumber('0x'))
+assert(not tonumber('x'))
+assert(not tonumber('x3'))
+assert(not tonumber('0x3.3.3'))   -- two decimal points
+assert(not tonumber('00x2'))
+assert(not tonumber('0x 2'))
+assert(not tonumber('0 x2'))
+assert(not tonumber('23x'))
+assert(not tonumber('- 0xaa'))
+assert(not tonumber('-0xaaP '))   -- no exponent
+assert(not tonumber('0x0.51p'))
+assert(not tonumber('0x5p+-2'))
 
 
 -- testing hexadecimal numerals
@@ -705,19 +705,19 @@ do   -- testing floor & ceil
   assert(eqT(math.tointeger(maxint), maxint))
   assert(eqT(math.tointeger(maxint .. ""), maxint))
   assert(eqT(math.tointeger(minint + 0.0), minint))
-  assert(math.tointeger(0.0 - minint) == nil)
-  assert(math.tointeger(math.pi) == nil)
-  assert(math.tointeger(-math.pi) == nil)
+  assert(not math.tointeger(0.0 - minint))
+  assert(not math.tointeger(math.pi))
+  assert(not math.tointeger(-math.pi))
   assert(math.floor(math.huge) == math.huge)
   assert(math.ceil(math.huge) == math.huge)
-  assert(math.tointeger(math.huge) == nil)
+  assert(not math.tointeger(math.huge))
   assert(math.floor(-math.huge) == -math.huge)
   assert(math.ceil(-math.huge) == -math.huge)
-  assert(math.tointeger(-math.huge) == nil)
+  assert(not math.tointeger(-math.huge))
   assert(math.tointeger("34.0") == 34)
-  assert(math.tointeger("34.3") == nil)
-  assert(math.tointeger({}) == nil)
-  assert(math.tointeger(0/0) == nil)    -- NaN
+  assert(not math.tointeger("34.3"))
+  assert(not math.tointeger({}))
+  assert(not math.tointeger(0/0))    -- NaN
 end