[SCM] gawk branch, feature/bool, created. gawk-4.1.0-4252-gb9931e8

[Arnold Robbins]

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- Log -----------------------------------------------------------------
http://git.sv.gnu.org/cgit/gawk.git/commit/?id=b9931e852ba21180c380639135f96cdcd0a3015f

commit b9931e852ba21180c380639135f96cdcd0a3015f
Author: Arnold D. Robbins <arnold@skeeve.com>
Date:   Fri Mar 5 14:26:15 2021 +0200

    Start on a bool type for gawk.

diff --git a/ChangeLog b/ChangeLog
index 89767c0..52b74a7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,19 @@
+2021-03-05         Arnold D. Robbins     <arnold@skeeve.com>
+
+       Start on a bool type for gawk.
+
+       * awk.h (BOOL): New flag value.
+       (make_bool_node): Add declaration of new function.
+       (bool_val): Check for BOOL along with NUMBER.
+       * builtin.c (do_typeof): Add support for BOOL.
+       * eval.c (flags2str): Ditto.
+       * gawkapi.h (awk_val_type): Add AWK_BOOL.
+       (awk_value_t): Add awk_bool_t element to the union and macro for it.
+       (struct gawk_api): Update the table of request/return values.
+       * main.c (load_procinfo_bools): New function.
+       (load_procinfo): Call it.
+       * node.c (make_bool_node): New function.
+
 2021-02-13         Arnold D. Robbins     <arnold@skeeve.com>
 
        * io.c (nextfile): Use the value of ARGC directly in the for
diff --git a/awk.h b/awk.h
index c9eec66..ee055f4 100644
--- a/awk.h
+++ b/awk.h
@@ -463,6 +463,7 @@ typedef struct exp_node {
                XARRAY          = 0x10000,
                NUMCONSTSTR     = 0x20000,      /* have string value for 
numeric constant */
                REGEX           = 0x40000,      /* this is a typed regex */
+               BOOL            = 0x80000,      /* this is a boolean value */
        } flags;
        long valref;
 } NODE;
@@ -1714,6 +1715,7 @@ extern NODE *r_force_number(NODE *n);
 extern NODE *r_format_val(const char *format, int index, NODE *s);
 extern NODE *r_dupnode(NODE *n);
 extern NODE *make_str_node(const char *s, size_t len, int flags);
+extern NODE *make_bool_node(bool value);
 extern NODE *make_typed_regex(const char *re, size_t len);
 extern void *more_blocks(int id);
 extern int parse_escape(const char **string_ptr);
@@ -1995,7 +1997,7 @@ static inline bool
 boolval(NODE *t)
 {
        (void) fixtype(t);
-       if ((t->flags & NUMBER) != 0)
+       if ((t->flags & (BOOL|NUMBER)) != 0)
                return ! is_zero(t);
        return (t->stlen > 0);
 }
diff --git a/bool.notes b/bool.notes
new file mode 100644
index 0000000..51ea726
--- /dev/null
+++ b/bool.notes
@@ -0,0 +1,47 @@
+Fri Mar  5 13:42:44 IST 2021
+============================
+
+Design Notes for a Boolean Type in Gawk
+
+1. At first glance, two new variables named TRUE and FALSE would make sense
+to be predefined values of boolean type.  However, since it's likely that
+many awk programs already use them, instead we'll add two new entries
+to PROCINFO: variables PROCINFO["true"] and PROCINFO["false"] of type bool.
+
+Assigning from them copies the bool type, thus they are "factories" of bool
+variables.
+
+2. They have numeric values 1 and 0 respectively, and string values
+"TRUE" and "FALSE".  Thus they differ from other variables where a
+"false" value must be zero and null.
+
+This implies all of the following:
+
+       print(PROCINFO["true"]) --> "TRUE"
+       print(PROCINFO["false"]) --> "FALSE"
+       Same for %s in printf
+       Same for bool_var ""
+       printf %d gives 0/1
+
+3. Function  bool(val)  converts val to bool, returning Boolean TRUE or FALSE.
+
+4. typeof() returns "bool".
+
+5. Numeric operators treat booleans as numbers.  asort() sorts booleans before
+numbers, and false before true.
+
+6. These string function generate a runtime fatal error
+if given an argument / target of boolean type:
+
+       substr  match   index   gensub  gsub
+       sub     length  split   patsplit
+       tolower toupper
+
+7. Updates to API needed for an additional type, and the table
+for requested vs. returns.
+
+8. The following extensions need revising:
+
+       - JSON extension
+       - dump / read array extensions
+       - what else?
diff --git a/builtin.c b/builtin.c
index 1b612f4..67a89bd 100644
--- a/builtin.c
+++ b/builtin.c
@@ -4112,7 +4112,10 @@ do_typeof(int nargs)
                }
                break;
        case Node_val:
-               switch (fixtype(arg)->flags & (STRING|NUMBER|USER_INPUT|REGEX)) 
{
+               switch (fixtype(arg)->flags & 
(STRING|NUMBER|USER_INPUT|REGEX|BOOL)) {
+               case BOOL:
+                       res = "bool";
+                       break;
                case NUMBER:
                        res = "number";
                        break;
diff --git a/eval.c b/eval.c
index 640f939..75c3932 100644
--- a/eval.c
+++ b/eval.c
@@ -455,6 +455,7 @@ flags2str(int flagval)
                { XARRAY, "XARRAY" },
                { NUMCONSTSTR, "NUMCONSTSTR" },
                { REGEX, "REGEX" },
+               { BOOL, "BOOL" },
                { 0,    NULL },
        };
 
diff --git a/gawkapi.h b/gawkapi.h
index 54130b1..3fd02df 100644
--- a/gawkapi.h
+++ b/gawkapi.h
@@ -366,7 +366,8 @@ typedef enum {
        AWK_STRNUM,
        AWK_ARRAY,
        AWK_SCALAR,             /* opaque access to a variable */
-       AWK_VALUE_COOKIE        /* for updating a previously created value */
+       AWK_VALUE_COOKIE,       /* for updating a previously created value */
+       AWK_BOOL
 } awk_valtype_t;
 
 /*
@@ -381,6 +382,7 @@ typedef struct awk_value {
                awk_array_t     a;
                awk_scalar_t    scl;
                awk_value_cookie_t vc;
+               awk_bool_t      b;
        } u;
 #define str_value      u.s
 #define strnum_value   str_value
@@ -391,6 +393,7 @@ typedef struct awk_value {
 #define array_cookie   u.a
 #define scalar_cookie  u.scl
 #define value_cookie   u.vc
+#define bool_value     u.b
 } awk_value_t;
 
 /*
@@ -567,26 +570,28 @@ typedef struct gawk_api {
 
                                
+-------------------------------------------------------+
                                |                   Type of Actual Value:       
        |
-                               
+--------+--------+--------+--------+-------+-----------+
-                               | String | Strnum | Number | Regex  | Array | 
Undefined |
-       
+-----------+-----------+--------+--------+--------+--------+-------+-----------+
-       |           | String    | String | String | String | String | false | 
false     |
-       |           
+-----------+--------+--------+--------+--------+-------+-----------+
-       |           | Strnum    | false  | Strnum | Strnum | false  | false | 
false     |
-       |           
+-----------+--------+--------+--------+--------+-------+-----------+
-       |           | Number    | Number | Number | Number | false  | false | 
false     |
-       |           
+-----------+--------+--------+--------+--------+-------+-----------+
-       |           | Regex     | false  | false  | false  | Regex  | false | 
false     |
-       |           
+-----------+--------+--------+--------+--------+-------+-----------+
-       |   Type    | Array     | false  | false  | false  | false  | Array | 
false     |
-       | Requested 
+-----------+--------+--------+--------+--------+-------+-----------+
-       |           | Scalar    | Scalar | Scalar | Scalar | Scalar | false | 
false     |
-       |           
+-----------+--------+--------+--------+--------+-------+-----------+
-       |           | Undefined | String | Strnum | Number | Regex  | Array | 
Undefined |
-       |           
+-----------+--------+--------+--------+--------+-------+-----------+
-       |           | Value     | false  | false  | false  | false  | false | 
false     |
-       |           | Cookie    |        |        |        |        |       |   
        |
-       
+-----------+-----------+--------+--------+--------+--------+-------+-----------+
+                               
+--------+--------+--------+--------+--------+-------+-----------+
+                               | String | Strnum | Number | Regex  | Bool   | 
Array | Undefined |
+       
+-----------+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | String    | String | String | String | String | String | 
false | false     |
+       |           
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | Strnum    | false  | Strnum | Strnum | false  | false  | 
false | false     |
+       |           
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | Number    | Number | Number | Number | false  | Number | 
false | false     |
+       |           
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | Regex     | false  | false  | false  | Regex  | false  | 
false | false     |
+       |           
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | Bool      | false  | false  | false  | false  | Bool   | 
false | false     |
+       |           
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |   Type    | Array     | false  | false  | false  | false  | false  | 
Array | false     |
+       | Requested 
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | Scalar    | Scalar | Scalar | Scalar | Scalar | Scalar | 
false | false     |
+       |           
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | Undefined | String | Strnum | Number | Regex  | Bool   | 
Array | Undefined |
+       |           
+-----------+--------+--------+--------+--------+--------+-------+-----------+
+       |           | Value     | false  | false  | false  | false  | false  | 
false | false     |
+       |           | Cookie    |        |        |        |        |        |  
     |           |
+       
+-----------+-----------+--------+--------+--------+--------+--------+-------+-----------+
        */
 
        /* Functions to handle parameters passed to the extension. */
diff --git a/main.c b/main.c
index 5b153bc..9833d84 100644
--- a/main.c
+++ b/main.c
@@ -980,7 +980,23 @@ load_procinfo_argv()
        // hook it into PROCINFO
        sub = make_string("argv", 4);
        assoc_set(PROCINFO_node, sub, argv_array);
+}
+
+/* load_procinfo_bools --- populate PROCINFO["true"] and PROCINFO["false"] */
+
+static void
+load_procinfo_bools()
+{
+       NODE *sub;
+       NODE *val;
+
+       val = make_bool_node(false);
+       sub = make_string("false", 5);
+       assoc_set(PROCINFO_node, sub, val);
 
+       val = make_bool_node(true);
+       sub = make_string("true", 4);
+       assoc_set(PROCINFO_node, sub, val);
 }
 
 /* load_procinfo --- populate the PROCINFO array */
@@ -1069,6 +1085,7 @@ load_procinfo()
        }
 #endif
        load_procinfo_argv();
+       load_procinfo_bools();
        return PROCINFO_node;
 }
 
diff --git a/node.c b/node.c
index c22c06a..dda90f0 100644
--- a/node.c
+++ b/node.c
@@ -1082,3 +1082,25 @@ more_blocks(int id)
 }
 
 #endif
+
+/* make_bool_node --- make a boolean-valued node */
+
+extern NODE *
+make_bool_node(bool value)
+{
+       NODE *val;
+       const char *sval;
+       AWKNUM nval;
+
+       sval = (value ? "TRUE" : "FALSE");
+       nval = (value ? 1.0 : 0.0);
+
+       val = make_number(nval);
+       val->stptr = estrdup(sval, strlen(sval));
+       val->stlen = strlen(sval);
+       val->flags &= ~NUMBER;
+       val->flags |= NUMCUR|STRCUR|BOOL;
+       val->stfmt = STFMT_UNUSED;
+
+       return val;
+}

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