From d2b5e10945b938033cb1007a330fa5cb6405df5d Mon Sep 17 00:00:00 2001 From: Pedro Date: Wed, 22 Oct 2014 15:43:27 +0200 Subject: [PATCH] added documentation to lexer and grammar files --- src/bison/bison_parser.y | 132 ++++++++++++++++++++++++++++----------- src/bison/flex_lexer.l | 52 ++++++++++----- 2 files changed, 133 insertions(+), 51 deletions(-) diff --git a/src/bison/bison_parser.y b/src/bison/bison_parser.y index e6b73cb..5ce8054 100644 --- a/src/bison/bison_parser.y +++ b/src/bison/bison_parser.y @@ -1,23 +1,43 @@ %{ - -/* - * parser.y file - * To generate the parser run: "bison parser.y" +/** + * bison_parser.y + * defines bison_parser.h + * outputs bison_parser.c + * + * Grammar File Spec: http://dinosaur.compilertools.net/bison/bison_6.html + * */ +/********************************* + ** Section 1: C Declarations + *********************************/ #include "Statement.h" #include "List.h" #include "bison_parser.h" #include "flex_lexer.h" -#include +#include int yyerror(Statement **expression, yyscan_t scanner, const char *msg) { - // Add error handling routine as needed + fprintf(stderr, "[Error] SQL Parser: %s\n", msg); + return 0; } %} +/********************************* + ** Section 2: Bison Parser Declarations + *********************************/ + +// Define the names of the created files +%output "bison_parser.c" +%defines "bison_parser.h" + +// Tell bison to create a reentrant parser +%define api.pure full + + +// Specify code that is included in the generated .h and .c files %code requires { #ifndef YYtypeDEF_YY_SCANNER_T @@ -27,14 +47,18 @@ typedef void* yyscan_t; } -%output "bison_parser.c" -%defines "bison_parser.h" - -%define api.pure +// Define additional parameters for yylex (http://www.gnu.org/software/bison/manual/html_node/Pure-Calling.html) %lex-param { yyscan_t scanner } + +// Define additional parameters for yyparse %parse-param { Statement **statement } %parse-param { yyscan_t scanner } + + +/********************************* + ** Define all data-types (http://www.gnu.org/software/bison/manual/html_node/Union-Decl.html) + *********************************/ %union { float number; char* sval; @@ -48,39 +72,58 @@ typedef void* yyscan_t; List* explist; } -%token SELECT FROM GROUP BY WHERE NOT AND OR + +/********************************* + ** Token Definition + *********************************/ +%token SELECT FROM GROUP BY WHERE NOT AND OR %token NAME STRING COMPARISON %token INTNUM + + +/********************************* + ** Non-Terminal types (http://www.gnu.org/software/bison/manual/html_node/Type-Decl.html) + *********************************/ %type statement %type select_statement %type table_name %type from_clause table_exp - %type expr column_name scalar_exp literal %type comparison_predicate predicate search_condition where_clause - %type table_ref_commalist %type expr_list group_clause + + + %% +/********************************* + ** Section 3: Grammar Definition + *********************************/ +// Defines our general input. +// TODO: Support list of statements input: statement opt_semicolon { *statement = $1; } ; +// All types of statements +// Atm: only select statements (future: insert, delete, etc...) statement: select_statement { $$ = $1; } | /* empty */ { $$ = NULL; } ; -////// TODO: -// join -// limit -// order by +/****************************** + ** Select Statements + ******************************/ +// TODO: join +// TODO: limit +// TODO: order by select_statement: SELECT expr_list from_clause where_clause group_clause { @@ -99,18 +142,20 @@ from_clause: FROM table_exp { $$ = $2; } ; + where_clause: WHERE search_condition { $$ = $2; } | /* empty */ { $$ = NULL; } ; +// TODO: having group_clause: GROUP BY expr_list { $$ = $3; } | /* empty */ { $$ = NULL; } ; - +// TODO: comma_list with mixed table names and select statements table_exp: table_ref_commalist { TableRef* t = new TableRef(eTableName); @@ -125,41 +170,34 @@ table_exp: ; +// TODO: multiple predicates search_condition: predicate ; + predicate: comparison_predicate ; + comparison_predicate: scalar_exp COMPARISON scalar_exp { $$ = makePredicate($1, $2, $3); } ; - +// TODO: Expression can also be scalar_exp expr: column_name | NAME '(' expr ')' { $$ = makeFunctionRef($1, $3); } ; - -/* Lists */ -expr_list: - expr { $$ = new List($1); } - | expr_list ',' expr { $1->push_back($3); $$ = $1; } +// TODO: Scalar expressions can also be arithmetic +scalar_exp: + column_name + | literal ; - -// TODO: add table_ref to include names and select queries -table_ref_commalist: - table_name { $$ = new List($1); } - | table_ref_commalist ',' table_name { $1->push_back($3); $$ = $1; } - ; -/* / Lists */ - - column_name: NAME { $$ = makeColumnRef($1); } ; @@ -174,13 +212,33 @@ literal: | INTNUM { $$ = makeFloatLiteral($1); } ; -scalar_exp: - column_name - | literal - ; opt_semicolon: ';' | /* empty */ ; + + +/****************************** + ** Lists + ******************************/ +expr_list: + expr { $$ = new List($1); } + | expr_list ',' expr { $1->push_back($3); $$ = $1; } + ; + +// TODO: add table_ref to include names and select queries +table_ref_commalist: + table_name { $$ = new List($1); } + | table_ref_commalist ',' table_name { $1->push_back($3); $$ = $1; } + ; + + + %% +/********************************* + ** Section 4: Additional C code + *********************************/ + +/* empty */ + diff --git a/src/bison/flex_lexer.l b/src/bison/flex_lexer.l index 036eb05..96c7081 100644 --- a/src/bison/flex_lexer.l +++ b/src/bison/flex_lexer.l @@ -1,32 +1,50 @@ -%{ - -/* - * lexer.l file - * To generate the lexical analyzer run: "flex lexer.l" +/** + * lexer + * + * */ + +/*************************** + ** Section 1: Definitions + ***************************/ +%{ + #include "Statement.h" #include "List.h" #include "bison_parser.h" - #include -#include -using namespace std; #define TOK(name) { return name; } %} +/*************************** + ** Section 2: Rules + ***************************/ +/* Define the output files */ +%option header-file="flex_lexer.h" +%option outfile="flex_lexer.c" -%option outfile="flex_lexer.c" header-file="flex_lexer.h" -%option warn nodefault -%option reentrant noyywrap never-interactive nounistd -%option bison-bridge +/* Make reentrant */ +%option reentrant bison-bridge + +/* performance tweeks */ +%option never-interactive batch + +/* other flags */ +%option noyywrap warn %option case-insensitive +/* %option nodefault */ + + +/*************************** + ** Section 3: Rules + ***************************/ %% -[ \t\n]+ ; +[ \t\n]+ /* skip whitespace */; SELECT TOK(SELECT) FROM TOK(FROM) @@ -69,8 +87,14 @@ OR TOK(OR) return STRING; } + + + %% +/*************************** + ** Section 3: User code + ***************************/ int yyerror(const char *msg) { - fprintf(stderr,"Error:%s\n",msg); return 0; + fprintf(stderr, "[Error] SQL Lexer: %s\n",msg); return 0; } \ No newline at end of file