doc: add some infos

- add some infos in doc
- add count limit prompt in query step

legacy/README.md

@@ -1,5 +1,51 @@
 # LCR Connector (Legacy)
 
-在3个元器件内，使用给定元器件数值列表快速找到目标数值元器件的最好拼接方式，支持电阻，电容，电感
+Get the resistor, capacitor, or inductor circuit which has the closest value for your given value within at most 3 devices.
 
-执行`uv run lcr-connector --help`来查阅参数手册。
+This is the legacy version of LCR Connector, although this is also refactored from true legacy version in modern Python.
+
+## Usage
+
+- Execute `uv sync` to configure the environment.
+- Execute `uv run lcr-connector --help` for the usage of LCR Connector.
+- After launch LCR Connector, you can see the help message in interactive console, or type `help` to see the help message.
+
+Additionaly, for using LCR Connector, you need 3 list files holding all possible device standard values which are available in your laboratory.
+Each of them represents a type of device respectively, resistor, capacitor, or inductor.
+These list files are basically like this:
+
+```
+100
+220
+270
+390
+470
+680
+1k
+1.2k
+1.5k
+2.2k
+3.3k
+4.7k
+6.8k
+10k
+47k
+100k
+1M
+```
+
+Supported units are:
+
+- n: Nano
+- p: Pico
+- u: Micro
+- m: Milli
+- k: Kilo
+- M: Mega
+- G: Giga
+
+There is no physical unit for the values in the list files.
+
+Unit is optional. If you don't specify a unit, the value is considered as a plain floating value.
+
+Unit is **case sensitive** to distinguish between milli and mega (e.g. 1m is milli, 1M is mega).

legacy/pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "lcr-connector"
 version = "1.0.0"
-description = "Use as much 3 devices to reach target value for resistor, capacitor and inductor."
+description = "Get the resistor, capacitor, or inductor circuit which has the closest value for your given value within at most 3 devices."
 readme = "README.md"
 authors = [
     { name = "yyc12345", email = "yyc12321@outlook.com" }

legacy/src/lcr_connector/__init__.py

@@ -149,8 +149,13 @@ class App:
             App.QuerySortPriority
         ).to_response_priority()
 
+        print("How may result are you expected?")
+        count_limit = self.__accept_count_value()
+
         # build request and ask resolver
-        request = Request(device_kind, target_value, tolerance, response_priority, 100)
+        request = Request(
+            device_kind, target_value, tolerance, response_priority, count_limit
+        )
         response = self.__resolver.resolve(request)
 
         # use page viewer to show result
@@ -217,10 +222,33 @@ class App:
             except ValueError:
                 print("Unknown command, please try again.")
 
+    def __accept_count_value(self) -> int:
+        MAX_COUNT: int = 50
+
+        while True:
+            self.__show_prompt_arrow()
+            words = input()
+            if words == "":
+                continue
+
+            try:
+                value = int(words)
+            except ValueError:
+                print("Wrong value, please try again.")
+                continue
+
+            if value > MAX_COUNT or value <= 0:
+                print("Wrong value, please try again.")
+            else:
+                return value
+
     def __accept_device_value(self) -> float:
         while True:
             self.__show_prompt_arrow()
             words = input()
+            if words == "":
+                continue
+
             value = self.__parse_human_readable_value(words)
             if value is None:
                 print("Wrong value, please try again.")
@@ -231,6 +259,8 @@ class App:
         while True:
             self.__show_prompt_arrow()
             words = input()
+            if words == "":
+                continue
 
             if words.endswith("%"):
                 value = self.__parse_plain_float(