src/inc/rql.h 1.1

Index: src/inc/rql.h
===================================================================
RCS file: src/inc/rql.h
diff -N src/inc/rql.h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ src/inc/rql.h	2 Dec 2009 19:09:53 -0000	1.1
@@ -0,0 +1,118 @@
+/* rql.h - interface to RQL (Ra Query Language - similar in syntax to SQL) parser and
+ * interpreter. */
+
+#ifndef RQL_H
+#define RQL_H
+
+#ifndef TOKENIZER_H
+#include "tokenizer.h"
+#endif
+
+enum rqlOp
+/* An operation in the parse tree. */
+    {
+    rqlOpUnknown,	/* Should not occur */
+    rqlOpLiteral,        /* Literal string or number. */
+    rqlOpSymbol,	/* A symbol name. */
+    rqlOpEq,	/* An equals comparison */
+    rqlOpNe,	/* A not equals comparison */
+
+    rqlOpStringToBoolean,
+    rqlOpIntToBoolean,
+    rqlOpDoubleToBoolean,
+    rqlOpStringToInt,
+    rqlOpStringToDouble,
+    rqlOpBooleanToInt,
+    rqlOpBooleanToDouble,
+    rqlOpIntToDouble,
+
+    rqlOpUnaryMinusDouble,
+
+    rqlOpGt,  /* Greater than comparison. */
+    rqlOpLt,  /* Less than comparison. */
+    rqlOpGe,  /* Greater than or equals comparison. */
+    rqlOpLe,  /* Less than or equals comparison. */
+    rqlOpLike, /* SQL wildcard compare. */
+
+    rqlOpAnd,     /* An and */
+    rqlOpOr,      /* An or */
+    rqlOpNot,	  /* A unary not. */
+    };
+
+char *rqlOpToString(enum rqlOp op);
+/* Return string representation of parse op. */
+
+enum rqlType
+/* A type */
+    {
+    rqlTypeBoolean = 1,
+    rqlTypeString = 2,
+    rqlTypeInt = 3,
+    rqlTypeDouble = 4,
+    };
+
+union rqlVal
+/* Some value of arbirary type that can be of any type corresponding to rqlType */
+    {
+    boolean b;
+    char *s;
+    int i;
+    double x;
+    };
+
+struct rqlEval
+/* Result of evaluation of parse tree. */
+    {
+    enum rqlType type;
+    union rqlVal val;
+    };
+
+struct rqlParse
+/* A rql parse-tree. */
+    {
+    struct rqlParse *next;	/* Points to younger sibling if any. */
+    struct rqlParse *children;	/* Points to oldest child if any. */
+    enum rqlOp op;		/* Operation at this node. */
+    enum rqlType type;		/* Return type of this operation. */
+    union rqlVal val;		/* Return value of this operation. */
+    };
+
+struct rqlStatement
+/* A parsed out RQL statement */
+    {
+    char *next;		/* Next in list */
+    char *command;	/* Generally the first word in the statement. */
+    struct slName *fieldList;	/* List of fields if any. */
+    struct slName *tableList;	/* List of tables if any. */
+    struct rqlParse *whereClause;	/* Where clause if any - tokenized. */
+    };
+
+void rqlValDump(union rqlVal val, enum rqlType type, FILE *f);
+/* Dump out value to file. */
+
+void rqlParseDump(struct rqlParse *p, int depth, FILE *f);
+/* Dump out rqlParse tree and children. */
+
+struct rqlParse *rqlParseExpression(struct tokenizer *tkz);
+/* Parse out a clause, usually a where clause. */
+
+struct rqlStatement *rqlStatementParse(struct lineFile *lf);
+/* Parse an RQL statement out of text */
+
+void rqlStatementFree(struct rqlStatement **pRql);
+/* Free up an rql statement. */
+
+void rqlStatementDump(struct rqlStatement *rql, FILE *f);
+/* Print out statement to file. */
+
+typedef char* (*RqlEvalLookup)(void *record, char *key);
+/* Callback for rqlEvalOnRecord to lookup a variable value. */
+
+struct rqlEval rqlEvalOnRecord(struct rqlParse *p, void *record, RqlEvalLookup lookup);
+/* Evaluate self on ra. */
+
+struct rqlEval rqlEvalCoerceToBoolean(struct rqlEval r);
+/* Return TRUE if it's a nonempty string or a non-zero number. */
+
+#endif /* RQL_H */
+