Add &&& and ||| operators

These are the short-circuit implementations of the `&&` and `||` operators.
positively-charged · Jan 31, 2017 · 80787d1 · 80787d1
1 parent f5e2426
commit 80787d1
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Showing 8 changed files with 76 additions and 11 deletions.
diff --git a/doc/grammar.txt b/doc/grammar.txt
@@ -619,9 +619,17 @@ assignment:
    <conditional> |=  <assignment>
 
 conditional:
+   <short-circuit-or>
+   <short-circuit-or> ? <expression> : <conditional>
+   <short-circuit-orshort-or> ? : <conditional>
+
+short-circuit-or:
+   <short-circuit-and>
+   <short-circuit-or> ||| <short-circuit-and>
+
+short-circuit-and:
    <logical-or>
-   <logical-or> ? <expression> : <conditional>
-   <logical-or> ? : <conditional>
+   <short-circuit-and> &&& <logical-or>
 
 logical-or:
    <logical-and>

diff --git a/src/codegen/expr.c b/src/codegen/expr.c
@@ -613,10 +613,11 @@ void write_logical( struct codegen* codegen, struct result* result,
    struct logical* logical ) {
    push_logical_operand( codegen, logical->lside, logical->lside_spec );
    struct c_jump* rside_jump = c_create_jump( codegen,
-      ( logical->op == LOP_OR ? PCD_IFNOTGOTO : PCD_IFGOTO ) );
+      ( logical->op == LOP_OR || logical->op == LOP_SHORTCIRCUITOR ?
+      PCD_IFNOTGOTO : PCD_IFGOTO ) );
    c_append_node( codegen, &rside_jump->node );
    c_pcd( codegen, PCD_PUSHNUMBER,
-      ( logical->op == LOP_OR ? 1 : 0 ) );
+      ( logical->op == LOP_OR || logical->op == LOP_SHORTCIRCUITOR ? 1 : 0 ) );
    struct c_jump* exit_jump = c_create_jump( codegen, PCD_GOTO );
    c_append_node( codegen, &exit_jump->node );
    struct c_point* rside_point = c_create_point( codegen );

diff --git a/src/parse/expr.c b/src/parse/expr.c
@@ -112,6 +112,8 @@ void read_op( struct parse* parse, struct expr_reading* reading ) {
    struct binary* bit_or = NULL;
    struct logical* log_and = NULL;
    struct logical* log_or = NULL;
+   struct logical* sc_and = NULL;
+   struct logical* sc_or = NULL;
    struct assign* assign = NULL;
 
    top:
@@ -300,6 +302,34 @@ void read_op( struct parse* parse, struct expr_reading* reading ) {
       goto top;
    }
 
+   // Short-circuit AND.
+   // -----------------------------------------------------------------------
+   if ( sc_and ) {
+      sc_and->rside = reading->node;
+      reading->node = &sc_and->node;
+      sc_and = NULL;
+   }
+   if ( parse->tk == TK_SHORTCIRCUITAND ) {
+      sc_and = alloc_logical( LOP_SHORTCIRCUITAND, &parse->tk_pos );
+      sc_and->lside = reading->node;
+      p_read_tk( parse );
+      goto top;
+   }
+
+   // Short-circuit OR.
+   // -----------------------------------------------------------------------
+   if ( sc_or ) {
+      sc_or->rside = reading->node;
+      reading->node = &sc_or->node;
+      sc_or = NULL;
+   }
+   if ( parse->tk == TK_SHORTCIRCUITOR ) {
+      sc_or = alloc_logical( LOP_SHORTCIRCUITOR, &parse->tk_pos );
+      sc_or->lside = reading->node;
+      p_read_tk( parse );
+      goto top;
+   }
+
    // Conditional
    // -----------------------------------------------------------------------
    if ( parse->lang == LANG_BCS && parse->tk == TK_QUESTION_MARK ) {

diff --git a/src/parse/phase.h b/src/parse/phase.h
@@ -172,6 +172,9 @@ enum tk {
    TK_REOPEN,
    TK_LET,
    TK_STRICT,
+   // 150
+   TK_SHORTCIRCUITOR,
+   TK_SHORTCIRCUITAND,
 
    TK_TOTAL,
 

diff --git a/src/parse/token/info.c b/src/parse/token/info.c
@@ -171,16 +171,19 @@ static struct token_info g_table[] = {
    ENTRY( "reopen", TKF_KEYWORD ),
    ENTRY( "let", TKF_KEYWORD ),
    ENTRY( "strict", TKF_KEYWORD ),
+   // 150
+   ENTRY( "|||", TKF_NONE ),
+   ENTRY( "&&&", TKF_NONE ),
 };
 #undef ENTRY
 
 const struct token_info* p_get_token_info( enum tk tk ) {
-   STATIC_ASSERT( TK_TOTAL == 150 );
+   STATIC_ASSERT( TK_TOTAL == 152 );
    return &g_table[ tk ];
 }
 
 void p_present_token( struct str* str, enum tk tk ) {
-   STATIC_ASSERT( TK_TOTAL == 150 );
+   STATIC_ASSERT( TK_TOTAL == 152 );
    switch ( tk ) {
    case TK_ID:
       str_append( str,

diff --git a/src/parse/token/source.c b/src/parse/token/source.c
@@ -1968,8 +1968,14 @@ void read_token( struct parse* parse, struct token* token ) {
    else if ( ch == '&' ) {
       ch = read_ch( parse );
       if ( ch == '&' ) {
-         tk = TK_LOG_AND;
          ch = read_ch( parse );
+         if ( ch == '&' ) {
+            tk = TK_SHORTCIRCUITAND;
+            ch = read_ch( parse );
+         }
+         else {
+            tk = TK_LOG_AND;
+         }
       }
       else if ( ch == '=' ) {
          tk = TK_ASSIGN_BIT_AND;
@@ -1983,8 +1989,14 @@ void read_token( struct parse* parse, struct token* token ) {
    else if ( ch == '|' ) {
       ch = read_ch( parse );
       if ( ch == '|' ) {
-         tk = TK_LOG_OR;
          ch = read_ch( parse );
+         if ( ch == '|' ) {
+            tk = TK_SHORTCIRCUITOR;
+            ch = read_ch( parse );
+         }
+         else {
+            tk = TK_LOG_OR;
+         }
       }
       else if ( ch == '=' ) {
          tk = TK_ASSIGN_BIT_OR;

diff --git a/src/semantic/expr.c b/src/semantic/expr.c
@@ -742,8 +742,14 @@ void fold_logical( struct semantic* semantic, struct logical* logical,
          UNREACHABLE();
       }
       switch ( logical->op ) {
-      case LOP_OR: l = ( l || r ); break;
-      case LOP_AND: l = ( l && r ); break;
+      case LOP_OR:
+      case LOP_SHORTCIRCUITOR:
+         l = ( l || r );
+         break;
+      case LOP_AND:
+      case LOP_SHORTCIRCUITAND:
+         l = ( l && r );
+         break;
       default:
          UNREACHABLE();
       }

diff --git a/src/task.h b/src/task.h
@@ -381,8 +381,10 @@ struct binary {
 struct logical {
    struct node node;
    enum {
+      LOP_SHORTCIRCUITOR,
+      LOP_SHORTCIRCUITAND,
       LOP_OR,
-      LOP_AND
+      LOP_AND,
    } op;
    struct node* lside;
    struct node* rside;