大更新：

1、完善SQL语法
2、移除node前端，只保留静态资源
3、写好安装脚本
4、做好linux适配

chusql-cli/src/ChuSQL/CLI/Script.hs

@@ -0,0 +1,123 @@
+{-# LANGUAGE OverloadedStrings #-}
+
+module ChuSQL.CLI.Script
+    ( Meta (..)
+    , parseMeta
+    , takeStatement
+    , statementComplete
+    , stripTerminator
+    , errorHint
+    , metaHelp
+    ) where
+
+import ChuSQL.CLI.Format (OutputFormat (..), formatName, parseFormat)
+import Data.Char (isSpace)
+import Data.Text (Text)
+import qualified Data.Text as T
+
+-- 交互层的纯逻辑：元命令、多行语句切分、错误提示。
+
+data Meta
+    = MetaQuit
+    | MetaHelp
+    | MetaDatabases
+    | MetaTables
+    | MetaDescribe Text
+    | MetaRoles
+    | MetaConnect Text
+    | MetaSetFormat OutputFormat
+    | MetaUnknown Text
+    deriving (Eq, Show)
+
+-- | 反斜杠开头的行是元命令，其余交给 SQL
+parseMeta :: Text -> Maybe Meta
+parseMeta raw = do
+    body <- T.stripPrefix "\\" (T.strip raw)
+    let (command, rest) = T.break isSpace body
+        argument = T.strip rest
+    pure $ case T.toLower command of
+        "q" -> MetaQuit
+        "quit" -> MetaQuit
+        "exit" -> MetaQuit
+        "?" -> MetaHelp
+        "h" -> MetaHelp
+        "help" -> MetaHelp
+        "l" -> MetaDatabases
+        "list" -> MetaDatabases
+        "dt" -> MetaTables
+        "tables" -> MetaTables
+        "d" | T.null argument -> MetaTables
+            | otherwise -> MetaDescribe argument
+        "dr" -> MetaRoles
+        "roles" -> MetaRoles
+        "c" -> connectTo argument
+        "connect" -> connectTo argument
+        "use" -> connectTo argument
+        "f" -> selectFormat argument
+        "format" -> selectFormat argument
+        other -> MetaUnknown other
+  where
+    connectTo argument
+        | T.null argument = MetaUnknown "c"
+        | otherwise = MetaConnect argument
+    selectFormat argument = maybe (MetaUnknown "format") MetaSetFormat (parseFormat argument)
+
+-- | 取出第一条以分号结束的语句与后面的残余；字符串与注释里的分号不算
+takeStatement :: Text -> Maybe (Text, Text)
+takeStatement = go ScanNormal [] . T.unpack
+  where
+    go _ _ [] = Nothing
+    go ScanNormal acc (';' : rest) = Just (T.strip (T.pack (reverse acc)), T.pack rest)
+    go ScanNormal acc ('-' : '-' : rest) = go ScanLineComment ('-' : '-' : acc) rest
+    go ScanNormal acc ('/' : '*' : rest) = go ScanBlockComment ('*' : '/' : acc) rest
+    go ScanNormal acc ('\'' : rest) = go ScanString ('\'' : acc) rest
+    go ScanNormal acc (ch : rest) = go ScanNormal (ch : acc) rest
+    go ScanString acc ('\'' : '\'' : rest) = go ScanString ('\'' : '\'' : acc) rest
+    go ScanString acc ('\'' : rest) = go ScanNormal ('\'' : acc) rest
+    go ScanString acc (ch : rest) = go ScanString (ch : acc) rest
+    go ScanLineComment acc ('\n' : rest) = go ScanNormal ('\n' : acc) rest
+    go ScanLineComment acc (ch : rest) = go ScanLineComment (ch : acc) rest
+    go ScanBlockComment acc ('*' : '/' : rest) = go ScanNormal ('/' : '*' : acc) rest
+    go ScanBlockComment acc (ch : rest) = go ScanBlockComment (ch : acc) rest
+
+data ScanState = ScanNormal | ScanString | ScanLineComment | ScanBlockComment
+
+-- | 攒下来的内容里有没有一条以分号结束的语句
+statementComplete :: Text -> Bool
+statementComplete = maybe False (const True) . takeStatement
+
+-- | 去掉结尾的空白与分号（-e 直接执行时用）
+stripTerminator :: Text -> Text
+stripTerminator raw = T.stripEnd (T.dropWhileEnd (== ';') (T.stripEnd raw))
+
+-- | 常见错误给一句怎么查
+errorHint :: Text -> Maybe Text
+errorHint message
+    | "unknown table" `T.isInfixOf` lowered = Just "run \\dt to list the tables of the current database"
+    | "unknown column" `T.isInfixOf` lowered = Just "run \\d <table> to see the columns of a table"
+    | "unknown database" `T.isInfixOf` lowered = Just "run \\l to list the databases"
+    | "syntax" `T.isInfixOf` lowered = Just "one statement at a time, and every statement ends with a semicolon"
+    | "invalid user name or password" `T.isInfixOf` lowered = Just "check --user and the password"
+    | "sign in first" `T.isInfixOf` lowered = Just "the session expired, restart the CLI"
+    | "too many failed sign-in attempts" `T.isInfixOf` lowered = Just "wait a few minutes before trying again"
+    | otherwise = Nothing
+  where
+    lowered = T.toLower message
+
+-- | \? 的帮助文本
+metaHelp :: Text
+metaHelp =
+    T.unlines
+        [ "SQL statements end with a semicolon; a statement may span several lines."
+        , ""
+        , "  \\q, \\quit          leave the CLI"
+        , "  \\?, \\h, \\help       show this help"
+        , "  \\l, \\list           list databases"
+        , "  \\dt, \\d             list tables"
+        , "  \\d <table>          describe a table"
+        , "  \\dr, \\roles         list roles with their grants and members"
+        , "  \\c <database>       switch database"
+        , "  \\f, \\format <fmt>   output format: " <> T.intercalate ", " (map formatName [FormatTable, FormatJson, FormatCsv])
+        , ""
+        , "At the chusql> prompt the arrow keys walk the SQL history."
+        ]