Grammar for uSQL, very simple SQL SELECT statements
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sestoft@dina.kvl.dk * 2001-02-22

Generating and compiling the lexer and parser:

mosmllex Sqllex.lex
mosmlyac -v Sqlpar.grm
mosmlc -c Absyn.sml
mosmlc -c -liberal Sqlpar.sig Sqlpar.sml
mosmlc -c Sqllex.sml
mosml -P full parse.sml


Grammar
-------

selstmt ::=                              program
        select exprs1 from names1

expr ::=
        *				  star (all fields)
        column				  a single column from a table
        NAME ( exprs )                    function application
        const                             constant literal
        ( expr )                          parenthesized expression
        not expr                          logical negation
        expr op expr                      arithmetic, comparison

exprs ::= 
					  no expressions
       exprs1				  at least one expression

exprs1 ::=                                comma-separated expression list
        expr
        expr ,  exprs1

names1 ::=                                comma-separated name list
        name
        name ,  names1


const ::=                                 constant literals
        CSTINT                            integer literal
        CSTBOOL                           boolean literal
        CSTSTRING                         string literal


Lexical matters: tokens and comments
------------------------------------

ID:         [`a`-`z``A`-`Z`][`a`-`z``A`-`Z``0`-`9``_`]*

            except for the keywords, which are:

	    and false from not or select" true

	    Keywords and identifiers may be written in lower case or
	    upper case, but are converted to lower case.

CSTINT:     -?[0-9]+

CSTBOOL:    false | true

CSTSTRING:  'any characters and embedded quotes '' even'
            
OP:         + - * / % = <> < <= > >= 


Comments:

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