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kc3-lang/libxkbcommon/src/xkbcomp/parser.y

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  • Author : Pierre Le Marre
    Date : 2025-01-16 23:22:40
    Hash : 4ac22263
    Message : keysyms: Check clashes between keysyms names and keywords Due to how our parser is implemented, keysyms names that are also valid keywords require special handling. Added a check for these clashes in the keysym generator. The only current clash, `section`, is already handled. Note that it means that e.g. `section`, `Section` and `sEcTiOn` all parse to the same keysym. This side effect is fine here, because *currently* there is no other keysym that clashes with any possible of the case variation of `section`. But in order to be extra cautious, we now test thoses clashes too. Hopefully we will never have a clash again, but while it is unlikely that we modify the keywords, the keysyms are not a frozen set.

  • src/xkbcomp/parser.y
  • /************************************************************
     Copyright (c) 1994 by Silicon Graphics Computer Systems, Inc.
    
     Permission to use, copy, modify, and distribute this
     software and its documentation for any purpose and without
     fee is hereby granted, provided that the above copyright
     notice appear in all copies and that both that copyright
     notice and this permission notice appear in supporting
     documentation, and that the name of Silicon Graphics not be
     used in advertising or publicity pertaining to distribution
     of the software without specific prior written permission.
     Silicon Graphics makes no representation about the suitability
     of this software for any purpose. It is provided "as is"
     without any express or implied warranty.
    
     SILICON GRAPHICS DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS
     SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
     AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL SILICON
     GRAPHICS BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
     DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
     DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
     OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION  WITH
     THE USE OR PERFORMANCE OF THIS SOFTWARE.
    
     ********************************************************/
    
    /*
     * The parser should work with reasonably recent versions of either
     * bison or byacc.  So if you make changes, try to make sure it works
     * in both!
     */
    
    %{
    #include "config.h"
    
    #include "xkbcomp/xkbcomp-priv.h"
    #include "xkbcomp/ast-build.h"
    #include "xkbcomp/parser-priv.h"
    #include "scanner-utils.h"
    #include "keysym.h"
    
    struct parser_param {
        struct xkb_context *ctx;
        struct scanner *scanner;
        XkbFile *rtrn;
        bool more_maps;
    };
    
    #define parser_err(param, error_id, fmt, ...) \
        scanner_err((param)->scanner, error_id, fmt, ##__VA_ARGS__)
    
    #define parser_warn(param, warning_id, fmt, ...) \
        scanner_warn((param)->scanner, warning_id, fmt, ##__VA_ARGS__)
    
    static void
    _xkbcommon_error(struct parser_param *param, const char *msg)
    {
        parser_err(param, XKB_ERROR_INVALID_SYNTAX, "%s", msg);
    }
    
    static bool
    resolve_keysym(struct parser_param *param, const char *name, xkb_keysym_t *sym_rtrn)
    {
        xkb_keysym_t sym;
    
        if (!name || istreq(name, "any") || istreq(name, "nosymbol")) {
            *sym_rtrn = XKB_KEY_NoSymbol;
            return true;
        }
    
        if (istreq(name, "none") || istreq(name, "voidsymbol")) {
            *sym_rtrn = XKB_KEY_VoidSymbol;
            return true;
        }
    
        sym = xkb_keysym_from_name(name, XKB_KEYSYM_NO_FLAGS);
        if (sym != XKB_KEY_NoSymbol) {
            *sym_rtrn = sym;
            check_deprecated_keysyms(parser_warn, param, param->ctx,
                                     sym, name, name, "%s", "");
            return true;
        }
    
        return false;
    }
    
    #define param_scanner param->scanner
    %}
    
    %define api.pure
    %lex-param      { struct scanner *param_scanner }
    %parse-param    { struct parser_param *param }
    
    %token
            END_OF_FILE     0
            ERROR_TOK       255
            XKB_KEYMAP      1
            XKB_KEYCODES    2
            XKB_TYPES       3
            XKB_SYMBOLS     4
            XKB_COMPATMAP   5
            XKB_GEOMETRY    6
            XKB_SEMANTICS   7
            XKB_LAYOUT      8
            INCLUDE         10
            OVERRIDE        11
            AUGMENT         12
            REPLACE         13
            ALTERNATE       14
            VIRTUAL_MODS    20
            TYPE            21
            INTERPRET       22
            ACTION_TOK      23
            KEY             24
            ALIAS           25
            GROUP           26
            MODIFIER_MAP    27
            INDICATOR       28
            SHAPE           29
            KEYS            30
            ROW             31
            SECTION         32
            OVERLAY         33
            TEXT            34
            OUTLINE         35
            SOLID           36
            LOGO            37
            VIRTUAL         38
            EQUALS          40
            PLUS            41
            MINUS           42
            DIVIDE          43
            TIMES           44
            OBRACE          45
            CBRACE          46
            OPAREN          47
            CPAREN          48
            OBRACKET        49
            CBRACKET        50
            DOT             51
            COMMA           52
            SEMI            53
            EXCLAM          54
            INVERT          55
            STRING          60
            INTEGER         61
            FLOAT           62
            IDENT           63
            KEYNAME         64
            PARTIAL         70
            DEFAULT         71
            HIDDEN          72
            ALPHANUMERIC_KEYS       73
            MODIFIER_KEYS           74
            KEYPAD_KEYS             75
            FUNCTION_KEYS           76
            ALTERNATE_GROUP         77
    
    %right  EQUALS
    %left   PLUS MINUS
    %left   TIMES DIVIDE
    %left   EXCLAM INVERT
    %left   OPAREN
    
    %start  XkbFile
    
    %union  {
            int64_t          num;
            enum xkb_file_type file_type;
            char            *str;
            xkb_atom_t      atom;
            enum merge_mode merge;
            enum xkb_map_flags mapFlags;
            xkb_keysym_t    keysym;
            ParseCommon     *any;
            struct { ParseCommon *head; ParseCommon *last; } anyList;
            ExprDef         *expr;
            struct { ExprDef *head; ExprDef *last; } exprList;
            VarDef          *var;
            struct { VarDef *head; VarDef *last; } varList;
            VModDef         *vmod;
            struct { VModDef *head; VModDef *last; } vmodList;
            InterpDef       *interp;
            KeyTypeDef      *keyType;
            SymbolsDef      *syms;
            ModMapDef       *modMask;
            GroupCompatDef  *groupCompat;
            LedMapDef       *ledMap;
            LedNameDef      *ledName;
            KeycodeDef      *keyCode;
            KeyAliasDef     *keyAlias;
            void            *geom;
            XkbFile         *file;
            struct { XkbFile *head; XkbFile *last; } fileList;
    }
    
    %type <num>     INTEGER FLOAT
    %type <str>     IDENT STRING
    %type <atom>    KEYNAME
    %type <num>     KeyCode Number Integer Float SignedNumber DoodadType
    %type <merge>   MergeMode OptMergeMode
    %type <file_type> XkbCompositeType FileType
    %type <mapFlags> Flag Flags OptFlags
    %type <str>     MapName OptMapName
    %type <atom>    FieldSpec Ident Element String
    %type <keysym>  KeySym
    %type <any>     Decl
    %type <anyList> DeclList
    %type <expr>    Expr Term Lhs Terminal ArrayInit Actions KeySyms
    %type <expr>    MultiKeySymList KeySymList MultiActionList ActionList Action Coord CoordList
    %type <exprList> OptExprList ExprList
    %type <var>     VarDecl SymbolsVarDecl
    %type <varList> VarDeclList SymbolsBody OptSymbolsBody
    %type <vmod>    VModDef
    %type <vmodList> VModDefList VModDecl
    %type <interp>  InterpretDecl InterpretMatch
    %type <keyType> KeyTypeDecl
    %type <syms>    SymbolsDecl
    %type <modMask> ModMapDecl
    %type <groupCompat> GroupCompatDecl
    %type <ledMap>  LedMapDecl
    %type <ledName> LedNameDecl
    %type <keyCode> KeyNameDecl
    %type <keyAlias> KeyAliasDecl
    %type <geom>    ShapeDecl SectionDecl SectionBody SectionBodyItem RowBody RowBodyItem
    %type <geom>    Keys Key OverlayDecl OverlayKeyList OverlayKey OutlineList OutlineInList
    %type <geom>    DoodadDecl
    %type <file>    XkbFile XkbMapConfig
    %type <fileList> XkbMapConfigList
    %type <file>    XkbCompositeMap
    
    %destructor { FreeStmt((ParseCommon *) $$); }
        <any> <expr> <var> <vmod> <interp> <keyType> <syms> <modMask> <groupCompat>
        <ledMap> <ledName> <keyCode> <keyAlias>
    %destructor { FreeStmt((ParseCommon *) $$.head); }
        <anyList> <exprList> <varList> <vmodList>
    /* The destructor also runs on the start symbol when the parser *succeeds*.
     * The `if` here catches this case. */
    %destructor { if (!param->rtrn) FreeXkbFile($$); } <file>
    %destructor { FreeXkbFile($$.head); } <fileList>
    %destructor { free($$); } <str>
    
    %%
    
    /*
     * An actual file may contain more than one map. However, if we do things
     * in the normal yacc way, i.e. aggregate all of the maps into a list and
     * let the caller find the map it wants, we end up scanning and parsing a
     * lot of unneeded maps (in the end we always just need one).
     * Instead of doing that, we make yyparse return one map at a time, and
     * then call it repeatedly until we find the map we need. Once we find it,
     * we don't need to parse everything that follows in the file.
     * This does mean that if we e.g. always use the first map, the file may
     * contain complete garbage after that. But it's worth it.
     */
    
    XkbFile         :       XkbCompositeMap
                            { $$ = param->rtrn = $1; param->more_maps = !!param->rtrn; (void) yynerrs; }
                    |       XkbMapConfig
                            { $$ = param->rtrn = $1; param->more_maps = !!param->rtrn; YYACCEPT; }
                    |       END_OF_FILE
                            { $$ = param->rtrn = NULL; param->more_maps = false; }
                    ;
    
    XkbCompositeMap :       OptFlags XkbCompositeType OptMapName OBRACE
                                XkbMapConfigList
                            CBRACE SEMI
                            { $$ = XkbFileCreate($2, $3, (ParseCommon *) $5.head, $1); }
                    ;
    
    XkbCompositeType:       XKB_KEYMAP      { $$ = FILE_TYPE_KEYMAP; }
                    |       XKB_SEMANTICS   { $$ = FILE_TYPE_KEYMAP; }
                    |       XKB_LAYOUT      { $$ = FILE_TYPE_KEYMAP; }
                    ;
    
    XkbMapConfigList :      XkbMapConfigList XkbMapConfig
                            { $$.head = $1.head; $$.last->common.next = &$2->common; $$.last = $2; }
                    |       XkbMapConfig
                            { $$.head = $$.last = $1; }
                    ;
    
    XkbMapConfig    :       OptFlags FileType OptMapName OBRACE
                                DeclList
                            CBRACE SEMI
                            {
                                $$ = XkbFileCreate($2, $3, $5.head, $1);
                            }
                    ;
    
    FileType        :       XKB_KEYCODES            { $$ = FILE_TYPE_KEYCODES; }
                    |       XKB_TYPES               { $$ = FILE_TYPE_TYPES; }
                    |       XKB_COMPATMAP           { $$ = FILE_TYPE_COMPAT; }
                    |       XKB_SYMBOLS             { $$ = FILE_TYPE_SYMBOLS; }
                    |       XKB_GEOMETRY            { $$ = FILE_TYPE_GEOMETRY; }
                    ;
    
    OptFlags        :       Flags                   { $$ = $1; }
                    |                               { $$ = 0; }
                    ;
    
    Flags           :       Flags Flag              { $$ = ($1 | $2); }
                    |       Flag                    { $$ = $1; }
                    ;
    
    Flag            :       PARTIAL                 { $$ = MAP_IS_PARTIAL; }
                    |       DEFAULT                 { $$ = MAP_IS_DEFAULT; }
                    |       HIDDEN                  { $$ = MAP_IS_HIDDEN; }
                    |       ALPHANUMERIC_KEYS       { $$ = MAP_HAS_ALPHANUMERIC; }
                    |       MODIFIER_KEYS           { $$ = MAP_HAS_MODIFIER; }
                    |       KEYPAD_KEYS             { $$ = MAP_HAS_KEYPAD; }
                    |       FUNCTION_KEYS           { $$ = MAP_HAS_FN; }
                    |       ALTERNATE_GROUP         { $$ = MAP_IS_ALTGR; }
                    ;
    
    DeclList        :       DeclList Decl
                            {
                                if ($2) {
                                    if ($1.head) {
                                        $$.head = $1.head; $1.last->next = $2; $$.last = $2;
                                    } else {
                                        $$.head = $$.last = $2;
                                    }
                                }
                            }
                            /*
                             * VModDecl is "inlined" directly into DeclList, i.e.
                             * each VModDef in the VModDecl is a separate Decl in
                             * the File.
                             */
                    |       DeclList OptMergeMode VModDecl
                            {
                                for (VModDef *vmod = $3.head; vmod; vmod = (VModDef *) vmod->common.next)
                                    vmod->merge = $2;
                                if ($1.head) {
                                    $$.head = $1.head; $1.last->next = &$3.head->common; $$.last = &$3.last->common;
                                } else {
                                    $$.head = &$3.head->common; $$.last = &$3.last->common;
                                }
                            }
                    |       { $$.head = $$.last = NULL; }
                    ;
    
    Decl            :       OptMergeMode VarDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    /*      OptMergeMode VModDecl - see above. */
                    |       OptMergeMode InterpretDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode KeyNameDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode KeyAliasDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode KeyTypeDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode SymbolsDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode ModMapDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode GroupCompatDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode LedMapDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode LedNameDecl
                            {
                                $2->merge = $1;
                                $$ = (ParseCommon *) $2;
                            }
                    |       OptMergeMode ShapeDecl          { $$ = NULL; }
                    |       OptMergeMode SectionDecl        { $$ = NULL; }
                    |       OptMergeMode DoodadDecl         { $$ = NULL; }
                    |       MergeMode STRING
                            {
                                $$ = (ParseCommon *) IncludeCreate(param->ctx, $2, $1);
                                free($2);
                            }
                    ;
    
    VarDecl         :       Lhs EQUALS Expr SEMI
                            { $$ = VarCreate($1, $3); }
                    |       Ident SEMI
                            { $$ = BoolVarCreate($1, true); }
                    |       EXCLAM Ident SEMI
                            { $$ = BoolVarCreate($2, false); }
                    ;
    
    KeyNameDecl     :       KEYNAME EQUALS KeyCode SEMI
                            { $$ = KeycodeCreate($1, $3); }
                    ;
    
    KeyAliasDecl    :       ALIAS KEYNAME EQUALS KEYNAME SEMI
                            { $$ = KeyAliasCreate($2, $4); }
                    ;
    
    VModDecl        :       VIRTUAL_MODS VModDefList SEMI
                            { $$ = $2; }
                    ;
    
    VModDefList     :       VModDefList COMMA VModDef
                            { $$.head = $1.head; $$.last->common.next = &$3->common; $$.last = $3; }
                    |       VModDef
                            { $$.head = $$.last = $1; }
                    ;
    
    VModDef         :       Ident
                            { $$ = VModCreate($1, NULL); }
                    |       Ident EQUALS Expr
                            { $$ = VModCreate($1, $3); }
                    ;
    
    InterpretDecl   :       INTERPRET InterpretMatch OBRACE
                                VarDeclList
                            CBRACE SEMI
                            { $2->def = $4.head; $$ = $2; }
                    ;
    
    InterpretMatch  :       KeySym PLUS Expr
                            { $$ = InterpCreate($1, $3); }
                    |       KeySym
                            { $$ = InterpCreate($1, NULL); }
                    ;
    
    VarDeclList     :       VarDeclList VarDecl
                            { $$.head = $1.head; $$.last->common.next = &$2->common; $$.last = $2; }
                    |       VarDecl
                            { $$.head = $$.last = $1; }
                    ;
    
    KeyTypeDecl     :       TYPE String OBRACE
                                VarDeclList
                            CBRACE SEMI
                            { $$ = KeyTypeCreate($2, $4.head); }
                    ;
    
    SymbolsDecl     :       KEY KEYNAME OBRACE
                                OptSymbolsBody
                            CBRACE SEMI
                            { $$ = SymbolsCreate($2, $4.head); }
                    ;
    
    OptSymbolsBody  :       SymbolsBody { $$ = $1; }
                    |                   { $$.head = $$.last = NULL; }
                    ;
    
    SymbolsBody     :       SymbolsBody COMMA SymbolsVarDecl
                            { $$.head = $1.head; $$.last->common.next = &$3->common; $$.last = $3; }
                    |       SymbolsVarDecl
                            { $$.head = $$.last = $1; }
                    ;
    
    SymbolsVarDecl  :       Lhs EQUALS Expr         { $$ = VarCreate($1, $3); }
                    |       Lhs EQUALS ArrayInit    { $$ = VarCreate($1, $3); }
                    |       Ident                   { $$ = BoolVarCreate($1, true); }
                    |       EXCLAM Ident            { $$ = BoolVarCreate($2, false); }
                    |       ArrayInit               { $$ = VarCreate(NULL, $1); }
                    ;
    
    ArrayInit       :       OBRACKET MultiKeySymList CBRACKET
                            { $$ = $2; }
                    |       OBRACKET MultiActionList CBRACKET
                            { $$ = $2; }
                    |       OBRACKET CBRACKET
                            { $$ = ExprEmptyList(); }
                    ;
    
    GroupCompatDecl :       GROUP Integer EQUALS Expr SEMI
                            { $$ = GroupCompatCreate($2, $4); }
                    ;
    
    ModMapDecl      :       MODIFIER_MAP Ident OBRACE ExprList CBRACE SEMI
                            { $$ = ModMapCreate($2, $4.head); }
                    ;
    
    LedMapDecl:             INDICATOR String OBRACE VarDeclList CBRACE SEMI
                            { $$ = LedMapCreate($2, $4.head); }
                    ;
    
    LedNameDecl:            INDICATOR Integer EQUALS Expr SEMI
                            { $$ = LedNameCreate($2, $4, false); }
                    |       VIRTUAL INDICATOR Integer EQUALS Expr SEMI
                            { $$ = LedNameCreate($3, $5, true); }
                    ;
    
    ShapeDecl       :       SHAPE String OBRACE OutlineList CBRACE SEMI
                            { $$ = NULL; }
                    |       SHAPE String OBRACE CoordList CBRACE SEMI
                            { (void) $4; $$ = NULL; }
                    ;
    
    SectionDecl     :       SECTION String OBRACE SectionBody CBRACE SEMI
                            { $$ = NULL; }
                    ;
    
    SectionBody     :       SectionBody SectionBodyItem     { $$ = NULL;}
                    |       SectionBodyItem                 { $$ = NULL; }
                    ;
    
    SectionBodyItem :       ROW OBRACE RowBody CBRACE SEMI
                            { $$ = NULL; }
                    |       VarDecl
                            { FreeStmt((ParseCommon *) $1); $$ = NULL; }
                    |       DoodadDecl
                            { $$ = NULL; }
                    |       LedMapDecl
                            { FreeStmt((ParseCommon *) $1); $$ = NULL; }
                    |       OverlayDecl
                            { $$ = NULL; }
                    ;
    
    RowBody         :       RowBody RowBodyItem     { $$ = NULL;}
                    |       RowBodyItem             { $$ = NULL; }
                    ;
    
    RowBodyItem     :       KEYS OBRACE Keys CBRACE SEMI { $$ = NULL; }
                    |       VarDecl
                            { FreeStmt((ParseCommon *) $1); $$ = NULL; }
                    ;
    
    Keys            :       Keys COMMA Key          { $$ = NULL; }
                    |       Key                     { $$ = NULL; }
                    ;
    
    Key             :       KEYNAME
                            { $$ = NULL; }
                    |       OBRACE ExprList CBRACE
                            { FreeStmt((ParseCommon *) $2.head); $$ = NULL; }
                    ;
    
    OverlayDecl     :       OVERLAY String OBRACE OverlayKeyList CBRACE SEMI
                            { $$ = NULL; }
                    ;
    
    OverlayKeyList  :       OverlayKeyList COMMA OverlayKey { $$ = NULL; }
                    |       OverlayKey                      { $$ = NULL; }
                    ;
    
    OverlayKey      :       KEYNAME EQUALS KEYNAME          { $$ = NULL; }
                    ;
    
    OutlineList     :       OutlineList COMMA OutlineInList
                            { $$ = NULL;}
                    |       OutlineInList
                            { $$ = NULL; }
                    ;
    
    OutlineInList   :       OBRACE CoordList CBRACE
                            { (void) $2; $$ = NULL; }
                    |       Ident EQUALS OBRACE CoordList CBRACE
                            { (void) $4; $$ = NULL; }
                    |       Ident EQUALS Expr
                            { FreeStmt((ParseCommon *) $3); $$ = NULL; }
                    ;
    
    CoordList       :       CoordList COMMA Coord
                            { (void) $1; (void) $3; $$ = NULL; }
                    |       Coord
                            { (void) $1; $$ = NULL; }
                    ;
    
    Coord           :       OBRACKET SignedNumber COMMA SignedNumber CBRACKET
                            { $$ = NULL; }
                    ;
    
    DoodadDecl      :       DoodadType String OBRACE VarDeclList CBRACE SEMI
                            { FreeStmt((ParseCommon *) $4.head); $$ = NULL; }
                    ;
    
    DoodadType      :       TEXT    { $$ = 0; }
                    |       OUTLINE { $$ = 0; }
                    |       SOLID   { $$ = 0; }
                    |       LOGO    { $$ = 0; }
                    ;
    
    FieldSpec       :       Ident   { $$ = $1; }
                    |       Element { $$ = $1; }
                    ;
    
    Element         :       ACTION_TOK
                            { $$ = xkb_atom_intern_literal(param->ctx, "action"); }
                    |       INTERPRET
                            { $$ = xkb_atom_intern_literal(param->ctx, "interpret"); }
                    |       TYPE
                            { $$ = xkb_atom_intern_literal(param->ctx, "type"); }
                    |       KEY
                            { $$ = xkb_atom_intern_literal(param->ctx, "key"); }
                    |       GROUP
                            { $$ = xkb_atom_intern_literal(param->ctx, "group"); }
                    |       MODIFIER_MAP
                            {$$ = xkb_atom_intern_literal(param->ctx, "modifier_map");}
                    |       INDICATOR
                            { $$ = xkb_atom_intern_literal(param->ctx, "indicator"); }
                    |       SHAPE
                            { $$ = xkb_atom_intern_literal(param->ctx, "shape"); }
                    |       ROW
                            { $$ = xkb_atom_intern_literal(param->ctx, "row"); }
                    |       SECTION
                            { $$ = xkb_atom_intern_literal(param->ctx, "section"); }
                    |       TEXT
                            { $$ = xkb_atom_intern_literal(param->ctx, "text"); }
                    ;
    
    OptMergeMode    :       MergeMode       { $$ = $1; }
                    |                       { $$ = MERGE_DEFAULT; }
                    ;
    
    MergeMode       :       INCLUDE         { $$ = MERGE_DEFAULT; }
                    |       AUGMENT         { $$ = MERGE_AUGMENT; }
                    |       OVERRIDE        { $$ = MERGE_OVERRIDE; }
                    |       REPLACE         { $$ = MERGE_REPLACE; }
                    |       ALTERNATE
                    {
                        /*
                         * This used to be MERGE_ALT_FORM. This functionality was
                         * unused and has been removed.
                         */
                        $$ = MERGE_DEFAULT;
                    }
                    ;
    
    OptExprList     :       ExprList        { $$ = $1; }
                    |                       { $$.head = $$.last = NULL; }
                    ;
    
    ExprList        :       ExprList COMMA Expr
                            { $$.head = $1.head; $$.last->common.next = &$3->common; $$.last = $3; }
                    |       Expr
                            { $$.head = $$.last = $1; }
                    ;
    
    Expr            :       Expr DIVIDE Expr
                            { $$ = ExprCreateBinary(EXPR_DIVIDE, $1, $3); }
                    |       Expr PLUS Expr
                            { $$ = ExprCreateBinary(EXPR_ADD, $1, $3); }
                    |       Expr MINUS Expr
                            { $$ = ExprCreateBinary(EXPR_SUBTRACT, $1, $3); }
                    |       Expr TIMES Expr
                            { $$ = ExprCreateBinary(EXPR_MULTIPLY, $1, $3); }
                    |       Lhs EQUALS Expr
                            { $$ = ExprCreateBinary(EXPR_ASSIGN, $1, $3); }
                    |       Term
                            { $$ = $1; }
                    ;
    
    Term            :       MINUS Term
                            { $$ = ExprCreateUnary(EXPR_NEGATE, $2->expr.value_type, $2); }
                    |       PLUS Term
                            { $$ = ExprCreateUnary(EXPR_UNARY_PLUS, $2->expr.value_type, $2); }
                    |       EXCLAM Term
                            { $$ = ExprCreateUnary(EXPR_NOT, EXPR_TYPE_BOOLEAN, $2); }
                    |       INVERT Term
                            { $$ = ExprCreateUnary(EXPR_INVERT, $2->expr.value_type, $2); }
                    |       Lhs
                            { $$ = $1;  }
                    |       FieldSpec OPAREN OptExprList CPAREN %prec OPAREN
                            { $$ = ExprCreateAction($1, $3.head); }
                    |       Terminal
                            { $$ = $1;  }
                    |       OPAREN Expr CPAREN
                            { $$ = $2;  }
                    ;
    
    MultiActionList :       MultiActionList COMMA Action
                            { $$ = ExprAppendActionList($1, $3); }
                    |       MultiActionList COMMA Actions
                            { $$ = ExprAppendMultiActionList($1, $3); }
                    |       Action
                            { $$ = ExprCreateActionList($1); }
                    |       Actions
                            { $$ = ExprCreateMultiActionList($1); }
                    ;
    
    ActionList      :       ActionList COMMA Action
                            { $$ = ExprAppendActionList($1, $3); }
                    |       Action COMMA Action
                            {
                                $$ = ExprCreateActionList($1);
                                $$ = ExprAppendActionList($$, $3);
                            }
                    ;
    
    Actions         :       OBRACE ActionList CBRACE
                            { $$ = $2; }
                    ;
    
    Action          :       FieldSpec OPAREN OptExprList CPAREN
                            { $$ = ExprCreateAction($1, $3.head); }
                    ;
    
    Lhs             :       FieldSpec
                            { $$ = ExprCreateIdent($1); }
                    |       FieldSpec DOT FieldSpec
                            { $$ = ExprCreateFieldRef($1, $3); }
                    |       FieldSpec OBRACKET Expr CBRACKET
                            { $$ = ExprCreateArrayRef(XKB_ATOM_NONE, $1, $3); }
                    |       FieldSpec DOT FieldSpec OBRACKET Expr CBRACKET
                            { $$ = ExprCreateArrayRef($1, $3, $5); }
                    ;
    
    Terminal        :       String
                            { $$ = ExprCreateString($1); }
                    |       Integer
                            { $$ = ExprCreateInteger($1); }
                    |       Float
                            { $$ = ExprCreateFloat(/* Discard $1 */); }
                    |       KEYNAME
                            { $$ = ExprCreateKeyName($1); }
                    ;
    
    MultiKeySymList :       MultiKeySymList COMMA KeySym
                            { $$ = ExprAppendKeysymList($1, $3); }
                    |       MultiKeySymList COMMA KeySyms
                            { $$ = ExprAppendMultiKeysymList($1, $3); }
                    |       KeySym
                            { $$ = ExprCreateKeysymList($1); }
                    |       KeySyms
                            { $$ = ExprCreateMultiKeysymList($1); }
                    ;
    
    KeySymList      :       KeySymList COMMA KeySym
                            { $$ = ExprAppendKeysymList($1, $3); }
                    |       KeySym COMMA KeySym
                            {
                                $$ = ExprCreateKeysymList($1);
                                $$ = ExprAppendKeysymList($$, $3);
                            }
                    ;
    
    KeySyms         :       OBRACE KeySymList CBRACE
                            { $$ = $2; }
                    ;
    
    KeySym          :       IDENT
                            {
                                if (!resolve_keysym(param, $1, &$$)) {
                                    parser_warn(
                                        param,
                                        XKB_WARNING_UNRECOGNIZED_KEYSYM,
                                        "unrecognized keysym \"%s\"",
                                        $1
                                    );
                                    $$ = XKB_KEY_NoSymbol;
                                }
                                free($1);
                            }
                            /* Handle keysym that is also a keyword  */
                    |       SECTION { $$ = XKB_KEY_section; }
                    |       Integer
                            {
                                if ($1 < XKB_KEYSYM_MIN) {
                                    parser_warn(
                                        param,
                                        XKB_WARNING_UNRECOGNIZED_KEYSYM,
                                        "unrecognized keysym \"%"PRId64"\"",
                                        $1
                                    );
                                    $$ = XKB_KEY_NoSymbol;
                                }
                                /* Special case for digits 0..9 */
                                else if ($1 < 10) {     /* XKB_KEY_0 .. XKB_KEY_9 */
                                    $$ = XKB_KEY_0 + (xkb_keysym_t) $1;
                                }
                                else {
                                    if ($1 <= XKB_KEYSYM_MAX) {
                                        $$ = (xkb_keysym_t) $1;
                                        check_deprecated_keysyms(
                                            parser_warn, param, param->ctx,
                                            $$, NULL, $$, "0x%"PRIx32, "");
                                    } else {
                                        parser_warn(
                                            param, XKB_WARNING_UNRECOGNIZED_KEYSYM,
                                            "unrecognized keysym \"0x%"PRIx64"\" "
                                            "(%"PRId64")", $1, $1
                                        );
                                        $$ = XKB_KEY_NoSymbol;
                                    }
                                    parser_warn(
                                        param, XKB_WARNING_NUMERIC_KEYSYM,
                                        "numeric keysym \"0x%"PRIx64"\" (%"PRId64")",
                                        $1, $1
                                    );
                                }
                            }
                    ;
    
    SignedNumber    :       MINUS Number    { $$ = -$2; }
                    |       Number          { $$ = $1; }
                    ;
    
    Number          :       FLOAT   { $$ = $1; }
                    |       INTEGER { $$ = $1; }
                    ;
    
    Float           :       FLOAT   { $$ = 0; }
                    ;
    
    Integer         :       INTEGER { $$ = $1; }
                    ;
    
    KeyCode         :       INTEGER { $$ = $1; }
                    ;
    
    Ident           :       IDENT   { $$ = xkb_atom_intern(param->ctx, $1, strlen($1)); free($1); }
                    |       DEFAULT { $$ = xkb_atom_intern_literal(param->ctx, "default"); }
                    ;
    
    String          :       STRING  { $$ = xkb_atom_intern(param->ctx, $1, strlen($1)); free($1); }
                    ;
    
    OptMapName      :       MapName { $$ = $1; }
                    |               { $$ = NULL; }
                    ;
    
    MapName         :       STRING  { $$ = $1; }
                    ;
    
    %%
    
    XkbFile *
    parse(struct xkb_context *ctx, struct scanner *scanner, const char *map)
    {
        int ret;
        XkbFile *first = NULL;
        struct parser_param param = {
            .scanner = scanner,
            .ctx = ctx,
            .rtrn = NULL,
            .more_maps = false,
        };
    
        /*
         * If we got a specific map, we look for it exclusively and return
         * immediately upon finding it. Otherwise, we need to get the
         * default map. If we find a map marked as default, we return it
         * immediately. If there are no maps marked as default, we return
         * the first map in the file.
         */
    
        while ((ret = yyparse(&param)) == 0 && param.more_maps) {
            if (map) {
                if (streq_not_null(map, param.rtrn->name))
                    return param.rtrn;
                else
                    FreeXkbFile(param.rtrn);
            }
            else {
                if (param.rtrn->flags & MAP_IS_DEFAULT) {
                    FreeXkbFile(first);
                    return param.rtrn;
                }
                else if (!first) {
                    first = param.rtrn;
                }
                else {
                    FreeXkbFile(param.rtrn);
                }
            }
            param.rtrn = NULL;
        }
    
        if (ret != 0) {
            /* Some error happend; clear the Xkbfiles parsed so far */
            FreeXkbFile(first);
            FreeXkbFile(param.rtrn);
            return NULL;
        }
    
        if (first)
            log_vrb(ctx, 5,
                    XKB_WARNING_MISSING_DEFAULT_SECTION,
                    "No map in include statement, but \"%s\" contains several; "
                    "Using first defined map, \"%s\"\n",
                    scanner->file_name, first->name);
    
        return first;
    }