Add typecheck.tablecheck

tests/tablecheck_test.lua

@@ -0,0 +1,36 @@
+local tablecheck = require("typecheck.tablecheck")
+
+local test = {}
+
+function test.all(t)
+	local tt = tablecheck([[(
+		a: number,
+		b: string,
+		c: string?
+	)]])
+
+	tt({
+		a = 1,
+		b = "",
+	})
+	tt({
+		a = 1,
+		b = "",
+		c = "",
+	})
+
+	t:has_error(tt, {
+		a = 1,
+		b = "",
+		c = 1,
+	})
+	t:has_error(tt, {
+		a = "",
+		b = "",
+	})
+	t:has_error(tt, {
+		a = 1,
+	})
+end
+
+return test

typecheck/tablecheck.lua

@@ -0,0 +1,37 @@
+local class = require("class")
+local lexer = require("typecheck.lexer")
+local Type = require("typecheck.Type")
+
+local nil_type = Type(nil)
+
+local tablecheck = class()
+
+function tablecheck:new(types)
+	local tokens = assert(lexer.lex(types))
+	self.param_names, self.param_types = assert(tokens:parse_params())
+	self.params_map = {}
+	for i, name in ipairs(self.param_names) do
+		self.params_map[name] = self.param_types[i]
+	end
+end
+
+local exp_got = "bad argument '%s' (%s expected, got %s)"
+
+function tablecheck:__call(t)
+	local params_map = self.params_map
+	local keys = {}
+	for k in pairs(t) do
+		keys[k] = true
+	end
+	for k in pairs(params_map) do
+		keys[k] = true
+	end
+	for k in pairs(keys) do
+		local _type = params_map[k] or nil_type
+		local v = t[k]
+		assert(_type:check(v), exp_got:format(k, _type, type(v)))
+	end
+	return t
+end
+
+return tablecheck