diff options
author | 2011-11-19 10:43:57 -0500 | |
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committer | 2011-11-19 10:43:57 -0500 | |
commit | 9f419ec6939626011308a380a39d3a7f8a403554 (patch) | |
tree | b8e125a96ec1466c542b24651ef1ce4027f21193 | |
parent | d50d1d215bf5777e29cc1ba3ae20eefad15e2d4a (diff) |
COALESCE
-rw-r--r-- | doc/manual.tex | 10 | ||||
-rw-r--r-- | lib/ur/basis.urs | 6 | ||||
-rw-r--r-- | src/monoize.sml | 22 | ||||
-rw-r--r-- | src/urweb.grm | 10 | ||||
-rw-r--r-- | src/urweb.lex | 1 | ||||
-rw-r--r-- | tests/coalesce.ur | 6 | ||||
-rw-r--r-- | tests/coalesce.urp | 4 |
7 files changed, 58 insertions, 1 deletions
diff --git a/doc/manual.tex b/doc/manual.tex index 84b300e7..03d29701 100644 --- a/doc/manual.tex +++ b/doc/manual.tex @@ -1709,6 +1709,15 @@ $$\begin{array}{l} \hspace{.1in} \to \mt{sql\_exp} \; \mt{tables} \; \mt{agg} \; \mt{exps} \; (\mt{option} \; \mt{t}) \to \mt{sql\_exp} \; \mt{tables} \; \mt{agg} \; \mt{exps} \; \mt{bool} \end{array}$$ +As another way of dealing with null values, there is also a restricted form of the standard \cd{COALESCE} function. +$$\begin{array}{l} + \mt{val} \; \mt{sql\_coalesce} : \mt{tables} ::: \{\{\mt{Type}\}\} \to \mt{agg} ::: \{\{\mt{Type}\}\} \to \mt{exps} ::: \{\mt{Type}\} \\ + \hspace{.1in} \to \mt{t} ::: \mt{Type} \\ + \hspace{.1in} \to \mt{sql\_exp} \; \mt{tables} \; \mt{agg} \; \mt{exps} \; (\mt{option} \; \mt{t}) \\ + \hspace{.1in} \to \mt{sql\_exp} \; \mt{tables} \; \mt{agg} \; \mt{exps} \; \mt{t} \\ + \hspace{.1in} \to \mt{sql\_exp} \; \mt{tables} \; \mt{agg} \; \mt{exps} \; \mt{t} +\end{array}$$ + We have generic nullary, unary, and binary operators. $$\begin{array}{l} \mt{con} \; \mt{sql\_nfunc} :: \mt{Type} \to \mt{Type} \\ @@ -2140,6 +2149,7 @@ $$\begin{array}{rrcll} &&& \ell & \textrm{primitive type literals} \\ &&& \mt{NULL} & \textrm{null value (injection of $\mt{None}$)} \\ &&& E \; \mt{IS} \; \mt{NULL} & \textrm{nullness test} \\ + &&& \mt{COALESCE}(E, E) & \textrm{take first non-null value} \\ &&& n & \textrm{nullary operators} \\ &&& u \; E & \textrm{unary operators} \\ &&& E \; b \; E & \textrm{binary operators} \\ diff --git a/lib/ur/basis.urs b/lib/ur/basis.urs index 73ee8e2b..f21faf38 100644 --- a/lib/ur/basis.urs +++ b/lib/ur/basis.urs @@ -474,6 +474,12 @@ val sql_is_null : tables ::: {{Type}} -> agg ::: {{Type}} -> exps ::: {Type} -> sql_exp tables agg exps (option t) -> sql_exp tables agg exps bool +val sql_coalesce : tables ::: {{Type}} -> agg ::: {{Type}} -> exps ::: {Type} + -> t ::: Type + -> sql_exp tables agg exps (option t) + -> sql_exp tables agg exps t + -> sql_exp tables agg exps t + val sql_if_then_else : tables ::: {{Type}} -> agg ::: {{Type}} -> exps ::: {Type} -> t ::: Type -> sql_exp tables agg exps bool diff --git a/src/monoize.sml b/src/monoize.sml index e570b4cb..d18b4d2a 100644 --- a/src/monoize.sml +++ b/src/monoize.sml @@ -2808,6 +2808,28 @@ fun monoExp (env, st, fm) (all as (e, loc)) = (L.ECApp ( (L.ECApp ( (L.ECApp ( + (L.EFfi ("Basis", "sql_coalesce"), _), _), + _), _), + _), _), + _), _)) => + let + val s = (L'.TFfi ("Basis", "string"), loc) + fun sc s = (L'.EPrim (Prim.String s), loc) + in + ((L'.EAbs ("x1", s, (L'.TFun (s, s), loc), + (L'.EAbs ("x1", s, s, + strcat [sc "COALESCE(", + (L'.ERel 1, loc), + sc ",", + (L'.ERel 0, loc), + sc ")"]), loc)), loc), + fm) + end + + | (L.ECApp ( + (L.ECApp ( + (L.ECApp ( + (L.ECApp ( (L.EFfi ("Basis", "sql_if_then_else"), _), _), _), _), _), _), diff --git a/src/urweb.grm b/src/urweb.grm index db8b6294..8e3fad90 100644 --- a/src/urweb.grm +++ b/src/urweb.grm @@ -244,7 +244,7 @@ fun tnamesOf (e, _) = | TRUE | FALSE | CAND | OR | NOT | COUNT | AVG | SUM | MIN | MAX | ASC | DESC - | INSERT | INTO | VALUES | UPDATE | SET | DELETE | NULL | IS + | INSERT | INTO | VALUES | UPDATE | SET | DELETE | NULL | IS | COALESCE | CURRENT_TIMESTAMP | NE | LT | LE | GT | GE | CCONSTRAINT | UNIQUE | CHECK | PRIMARY | FOREIGN | KEY | ON | NO | ACTION | RESTRICT | CASCADE | REFERENCES @@ -1881,6 +1881,14 @@ sqlexp : TRUE (sql_inject (EVar (["Basis"], "True", In in (EApp (e, sqlexp), loc) end) + | COALESCE LPAREN sqlexp COMMA sqlexp RPAREN + (let + val loc = s (COALESCEright, sqlexp2right) + val e = (EVar (["Basis"], "sql_coalesce", Infer), loc) + val e = (EApp (e, sqlexp1), loc) + in + (EApp (e, sqlexp2), loc) + end) | fname LPAREN sqlexp RPAREN (let val loc = s (fnameleft, RPARENright) diff --git a/src/urweb.lex b/src/urweb.lex index a989d933..8e8b0a12 100644 --- a/src/urweb.lex +++ b/src/urweb.lex @@ -499,6 +499,7 @@ xint = x[0-9a-fA-F][0-9a-fA-F]; <INITIAL> "DELETE" => (Tokens.DELETE (pos yypos, pos yypos + size yytext)); <INITIAL> "NULL" => (Tokens.NULL (pos yypos, pos yypos + size yytext)); <INITIAL> "IS" => (Tokens.IS (pos yypos, pos yypos + size yytext)); +<INITIAL> "COALESCE" => (Tokens.COALESCE (pos yypos, pos yypos + size yytext)); <INITIAL> "CONSTRAINT"=> (Tokens.CCONSTRAINT (pos yypos, pos yypos + size yytext)); <INITIAL> "UNIQUE" => (Tokens.UNIQUE (pos yypos, pos yypos + size yytext)); diff --git a/tests/coalesce.ur b/tests/coalesce.ur new file mode 100644 index 00000000..5ee8cf19 --- /dev/null +++ b/tests/coalesce.ur @@ -0,0 +1,6 @@ +table t : { A : option int } + +fun main () : transaction page = + queryX (SELECT COALESCE(t.A, 13) + FROM t) + (fn r => <xml>{[r.1]},</xml>) diff --git a/tests/coalesce.urp b/tests/coalesce.urp new file mode 100644 index 00000000..7d7decee --- /dev/null +++ b/tests/coalesce.urp @@ -0,0 +1,4 @@ +database dbname=test +sql coalesce.sql + +coalesce |