From 6b377719c10d5ab3343fd5221f99a4a21008e25a Mon Sep 17 00:00:00 2001
From: Sébastien Dailly <sebastien@dailly.me>
Date: Thu, 14 Mar 2024 08:26:58 +0100
Subject: Initial commit

---
 lib/configuration/expression_parser.mly | 185 ++++++++++++++++++++++++++++++++
 1 file changed, 185 insertions(+)
 create mode 100644 lib/configuration/expression_parser.mly

(limited to 'lib/configuration/expression_parser.mly')

diff --git a/lib/configuration/expression_parser.mly b/lib/configuration/expression_parser.mly
new file mode 100644
index 0000000..1304c4d
--- /dev/null
+++ b/lib/configuration/expression_parser.mly
@@ -0,0 +1,185 @@
+%token <string>IDENT
+%token L_PAREN 
+%token R_PAREN 
+%token L_BRACKET R_BRACKET
+%token COLUMN  
+%token DOT 
+%token <string>LITERAL
+%token <string>INTEGER
+%token COMA
+%token EOF
+%token CONCAT_OPERATOR
+
+%token <ImportExpression.T.binary_operator>BINARY_OPERATOR
+%token <ImportExpression.T.binary_operator>INEQUALITY_OPERATOR
+%token <ImportExpression.T.binary_operator>EQUALITY_OPERATOR
+%token <ImportExpression.T.binary_operator>BOOL_OPERATOR
+
+%start <ImportDataTypes.Path.t ImportExpression.T.t> path_expr
+%start <ImportDataTypes.Path.column ImportExpression.T.t> column_expr
+
+%right BOOL_OPERATOR
+%right INEQUALITY_OPERATOR EQUALITY_OPERATOR
+%right CONCAT_OPERATOR BINARY_OPERATOR 
+
+%{
+
+    let function_of_name param f = 
+      match (String.lowercase_ascii f, param) with
+        | "nvl", _ -> 
+            ImportExpression.T.Nvl param 
+        | "join", (ImportExpression.T.Literal sep:: tl) -> 
+            ImportExpression.T.Join (sep, tl)
+        | "join", (ImportExpression.T.Empty:: tl) -> 
+            ImportExpression.T.Join ("", tl)
+        | "upper", _ -> 
+            ImportExpression.T.Function' (ImportExpression.T.Upper, param)
+        | "trim", _ -> 
+            ImportExpression.T.Function' (ImportExpression.T.Trim, param)
+        | other, _ -> 
+            ImportExpression.T.Function (other, param)
+
+%}
+
+%%
+
+path_expr: 
+    | expr_(path_, EOF) EOF { $1 }
+    | EOF { ImportExpression.T.Empty }
+column_expr: 
+    | expr_(column_, EOF) EOF { $1 }
+    | EOF { ImportExpression.T.Empty }
+
+
+path_: 
+    | COLUMN
+      column = IDENT    
+        { ImportExpression.T.Path 
+             Syntax.Path.{ alias = None
+            ; column = ImportCSV.Csv.column_of_string column
+            }
+        }
+
+    | COLUMN
+      table = IDENT
+      DOT
+      column = IDENT    
+      { ImportExpression.T.Path
+             Syntax.Path.{ alias = Some table 
+            ; column = ImportCSV.Csv.column_of_string column}
+      }
+
+column_: 
+    | COLUMN
+      column = IDENT
+        { try ImportExpression.T.Path (ImportCSV.Csv.column_of_string column)
+        with _ -> ImportExpression.T.Literal column }
+
+arguments(PATH):
+    | L_PAREN
+      expr = separated_list(COMA, expr_(PATH, COMA))
+      R_PAREN
+        { expr }
+
+group(PATH):
+    | L_BRACKET
+      expr = separated_list(COMA, expr_(PATH, COMA))
+      R_BRACKET
+        { expr }
+
+fixed(PATH):
+    | d = INTEGER
+        { ImportExpression.T.Integer d }
+    | l = LITERAL 
+        {
+          if String.equal String.empty l then 
+            ImportExpression.T.Empty 
+          else
+            ImportExpression.T.Literal l
+        }
+
+%inline boperator: 
+        | e = BINARY_OPERATOR { e }
+        | e = INEQUALITY_OPERATOR { e }
+        | e = EQUALITY_OPERATOR { e }
+        | e = BOOL_OPERATOR { e }
+
+(* The expression evaluation receveive in parameters :
+    1. the way to buidl a path, as we have two distinct ways to build them in
+       the case of externals (the external_key does not allow a table name)
+    2. a phantom type telling wich kind of element will end the expression.
+       This can be EOF for the root expression, or COMA when inside a function.
+       This prevent merlin to optimize thoses two path, and allow more precise
+       error messages. *)
+expr_(PATH, ENDING_PHANTOM):
+    | L_PAREN
+      e  = expr_(PATH, R_PAREN)
+      R_PAREN
+      { ImportExpression.T.Expr e
+      }
+    |
+      p1 = expr_(PATH, ENDING_PHANTOM)
+      CONCAT_OPERATOR
+      p2 = expr_(PATH, COMA)
+        { match p2 with 
+           | ImportExpression.T.Concat args ->  ImportExpression.T.Concat (p1::args)
+           | _ -> ImportExpression.T.Concat (p1::p2::[]) 
+        }
+    | p1 = expr_(PATH, ENDING_PHANTOM)
+
+      op = boperator
+      p2 = expr_(PATH, COMA)
+      { ImportExpression.T.BOperator (op, p1, p2) }
+
+    | p1 = expr_(PATH, ENDING_PHANTOM)
+      op = EQUALITY_OPERATOR
+      p2 = group(PATH)
+      { ImportExpression.T.GEquality(op, p1, p2) }
+
+
+        
+    | p = PATH      
+        { p }
+    | f = fixed(PATH)
+        { f }
+    | s = IDENT
+      args = arguments(PATH)
+      { function_of_name args s }
+    | 
+      s = IDENT
+      L_PAREN
+      opt_arg = opt_arg(PATH, COMA)?
+      args1 = group(PATH)
+      COMA
+      args2 = group(PATH)
+      R_PAREN
+      { let window_name = ImportExpression.T.window_of_name s opt_arg in
+        ImportExpression.T.Window (window_name, args1, args2) }
+(*
+    | (* This case is here to describe a window function which has 2 arguments
+         level. 
+         I’m not completely satisfied with it, as it prevent the ability to
+         create a exprpression block with parens arround. *) 
+      s = IDENT
+      L_PAREN
+      opt_arg = opt_arg(PATH, COMA)?
+      args1 = arguments(PATH)
+      COMA
+      args2 = arguments(PATH)
+      R_PAREN
+      { let window_name = ImportExpression.T.window_of_name s opt_arg in
+        let expr = ImportExpression.T.Window (window_name, args1, args2) in 
+
+        let expr_repr = ImportExpression.Repr.repr ~top:true  (fun _ -> "")
+        expr in 
+        Printf.printf "Deprecated syntax in \"%s\" use [] instead of ()\n" expr_repr;
+
+
+        expr 
+      }
+*)
+
+opt_arg(PATH, SEP): 
+    | expr = expr_(PATH, COMA)
+      SEP
+        { expr }
-- 
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