Implement a find() macro

This macro looks at each cell along some stride through the sheet,
  returning the location of the first cell encountered at which a given
  expression evaluates to true, or boolean false otherwise.

  To make this more useful, this change also revamps the handling of
  boolean values, making them much more permissive and coercing to boolean type
  in fewer circumstances. It adds the bool() type conversion for explicitly
  coercing to boolean type, and fixes a small issue with reading hex-formatted
  floating-point values ('p' can be used as an exponent indicator).

  Closes #64.

doc/teapot.lyx

@@ -4960,7 +4960,7 @@ and
 
 \series default
 \emph default
-y evaluates to the logical conjunction of boolean values 
+y evaluates to the logical conjunction of values 
 \emph on
 x
 \emph default
@@ -4979,6 +4979,32 @@ y
 \emph default
  is never evaluated, and so does not affect the value even if it is an error,
  for example.
+ In determining the value, the boolean conversions of 
+\emph on
+x
+\emph default
+ and 
+\emph on
+y
+\emph default
+ are used (see the description of the bool() function below), but the actual
+ value returned is either that of 
+\emph on
+x
+\emph default
+ or 
+\emph on
+y
+\emph default
+, namely, 
+\emph on
+x
+\emph default
+ if it corresponds to a boolean false value or 
+\emph on
+y
+\emph default
+ otherwise.
 \end_layout
 
 \begin_layout Description
@@ -5024,6 +5050,15 @@ and
 x
 \emph default
  is true.
+ Also in similar fashion, the value is 
+\emph on
+x
+\emph default
+ if it corresponds to a boolean true value and 
+\emph on
+y
+\emph default
+ otherwise.
 \end_layout
 
 \begin_layout Description
@@ -6442,24 +6477,41 @@ or
 \end_layout
 
 \begin_layout Description
-bool currently only acts as a keyword to 
+
+\series medium
+bool
+\begin_inset space ~
+\end_inset
+
+
+\series default
+bool
+\series medium
+[([
+\emph on
+x
+\emph default
+])]
+\series default
+ Converts 
+\emph on
+x 
+\emph default
+to a boolean value.
+ This is very permissive; error values are unaffected; empty, integer 0,
+ float 0.0, and boolean false values are false, and everything else is true.
+ If 
+\emph on
+x
+\emph default
+ is omitted, defaults to the value of the current cell.
+ If the parentheses are omitted as well, acts as a keyword, for example
+ for testing types with 
 \family sans
 \series bold
 is
 \series default
-(); 
+().
-\family default
-there are not currently any conversions to boolean type.
- Use e.g.
-
-\family sans
- 
-\shape italic
-expr
-\shape default
- != 0 
-\family default
-to obtain a boolean value from a numerical expression.
 \end_layout
 
 \begin_layout Description
@@ -6755,6 +6807,69 @@ function identifier,
  There is probably little practical call for this type.
 \end_layout
 
+\begin_layout Description
+find
+\series medium
+(
+\emph on
+expr
+\emph default
+,
+\emph on
+
+\begin_inset space ~
+\end_inset
+
+
+\emph default
+location
+\emph on
+
+\begin_inset space ~
+\end_inset
+
+stride
+\emph default
+[,location
+\emph on
+
+\begin_inset space ~
+\end_inset
+
+start
+\emph default
+]) examines cells in turn, returning the location of the first one at which
+ 
+\series default
+\emph on
+expr
+\emph default
+ evaluates to true, or boolean false if the boundary of the sheet is encountered.
+ The second argument 
+\emph on
+stride
+\emph default
+ must not have all zero components, and is added to the location being examined
+ at each iteration.
+ Often it is useful to use a direction constant like 
+\family sans
+\series bold
+up
+\family default
+\series default
+ for the stride.
+ The search begins at location 
+\emph on
+start
+\emph default
+, which defaults to the current location plus the 
+\emph on
+stride
+\emph default
+ if it is not specified.
+ 
+\end_layout
+
 \begin_layout Description
 
 \series medium

src/common/eval.c

@@ -946,33 +946,42 @@ Token tne(Token l, Token r)
 }
 /*}}}*/
 
+/* tbool    -- token considered as a boolean value */ /*{{{*/
+Token tbool(Token x)
+{
+  Token result;
+  result.type = BOOL;
+  result.u.bl = true;
+  switch (x.type) {
+    case EEK: return x;
+    case EMPTY: result.u.bl = false; return result;
+    case BOOL: return x;
+    case INT: result.u.bl = (x.u.integer != 0); return result;
+    case STRING: result.u.bl = (strlen(x.u.string) > 0); return result;
+    case FLOAT: result.u.bl = x.u.flt != 0.0; return result;
+    default: break; /* everything else is true */
+  }
+  return result;
+}
+/*}}}*/
+
 /* tor      -- logical or of two tokens */ /*{{{*/
 Token tor(Token l, Token r)
 {
-  switch (l.type) {
+  if (l.type == EEK) return tcopy(l);
-    case EEK: return tcopy(l);
+  Token lbool = tbool(l);
-    case EMPTY : return tcopy(r);
+  if (lbool.u.bl) return tcopy(l);
-    case BOOL:
+  return tcopy(r);
-      if (r.type == EMPTY || l.u.bl) return l;
-      return r;
-    default: break;
-  }
-  return operand_type_error("or: ", l.type, r.type);
 }
 /*}}}*/
 
 /* tand      -- logical and of two tokens */ /*{{{*/
 Token tand(Token l, Token r)
 {
-  switch (l.type) {
+  if (l.type == EEK) return tcopy(l);
-    case EEK: return tcopy(l);
+  Token lbool = tbool(l);
-    case EMPTY : return l;
+  if (!lbool.u.bl) return tcopy(l);
-    case BOOL:
+  return tcopy(r);
-      if (!l.u.bl) return l;
-      return r;
-    default: break;
-  }
-  return operand_type_error("and: ", l.type, r.type);
 }
 /*}}}*/
 

src/common/eval.h

@@ -25,6 +25,7 @@ Token tgt(Token l, Token r);
 Token teq(Token l, Token r);
 Token tabouteq(Token l, Token r);
 Token tne(Token l, Token r);
+Token tbool(Token x);
 Token tor(Token l, Token r);
 Token tand(Token l, Token r);
 #endif

src/common/func.c

@@ -512,6 +512,54 @@ static Token dim_func(FunctionIdentifier self, int argc, const Token argv[])
 }
 /*}}}/
 
+  /* find_macro -- search for a cell satisfying some expression */ /*{{{*/
+static Token find_macro(FunctionIdentifier self, int argc, const Token argv[])
+{
+  const char *usage = _("Usage: find(expr, loc_stride[, loc_start])");
+  Token result;
+  if (argc < 2 || argc > 3) return duperror(&result, usage);
+  Token tstride = evaltoken(argv[1], FULL);
+  if (tstride.type == EEK) return tstride;
+  if (tstride.type != LOCATION) {
+    tfree(&tstride);
+    return duperror(&result, usage);
+  }
+  Location stride;
+  LOCATION_GETS(stride, tstride.u.location);
+  if (stride[X] == 0 && stride[Y] == 0 && stride[Z] == 0)
+    return duperror(&result, _("Stride in find() must be nonzero."));
+  Location current;
+  if (argc == 3) {
+    Token tstart = evaltoken(argv[2], FULL);
+    if (tstart.type == EEK) return tstart;
+    if (tstart.type != LOCATION) {
+      tfree(&tstart);
+      return duperror(&result, usage);
+    }
+    LOCATION_GETS(current, tstart.u.location);
+  } else {
+    LOCATION_GETS(current, upd_l);
+    LOCATION_ADD(current, stride);
+  }
+  result.type = BOOL;
+  result.u.bl = false;
+  while (IN_OCTANT(current) && LOC_WITHIN(upd_sheet, current)) {
+    Token tprobe = evaluate_at(argv[0], upd_sheet, current);
+    Token probe = tbool(tprobe);
+    tfree_protected(&tprobe, probe);
+    if (probe.type == EEK) return probe;
+    assert(probe.type == BOOL);
+    if (probe.u.bl) {
+      result.type = LOCATION;
+      LOCATION_GETS(result.u.location, current);
+      return result;
+    }
+    LOCATION_ADD(current, stride);
+  }
+  return result;
+}
+/*}}}*/
+
 /* bit_func -- common implementation of the bitwise functions */ /*{{{*/
 static Token bit_func(FunctionIdentifier self, int argc, const Token argv[])
 {
@@ -637,6 +685,21 @@ static Token self_func(FunctionIdentifier self, int argc, const Token argv[])
 }
 /*}}}*/
 
+static Token bool_func(FunctionIdentifier self, int argc, const Token argv[])
+{
+  assert(self == FUNC_BOOL);
+  Token arg;
+  switch (argc) {
+    case -1: return self_func(self, argc, argv);
+    case 0: arg = recompvalue(upd_sheet, upd_l); break;
+    case 1: arg = tcopy(argv[0]); break;
+    default: return duperror(&arg, _("Usage:bool[([val])]"));
+  }
+  Token result = tbool(arg);
+  tfree_protected(&arg, result);
+  return result;
+}
+
 /* empty -- ignores arguments and returns empty value */ /*{{{*/
 static Token empty_func(FunctionIdentifier self, int argc, const Token argv[])
 {
@@ -688,48 +751,6 @@ static Token float_func(FunctionIdentifier self, int argc, const Token argv[])
 }
 /*}}}*/
 
-/* number -- convert to most appropriate number type */ /*{{{*/
-static Token number_func(FunctionIdentifier self, int argc, const Token argv[])
-{
-  assert(self == FUNC_NUMBER);
-  const char *usage = _("Usage: number[([bool|empty|int|float|string x])]");
-  Token result, arg;
-  result.type = INT;
-  result.u.integer = 0;
-
-  switch (argc) {
-    case -1: return self_func(self, argc, argv);
-    case 0: arg = recompvalue(upd_sheet, upd_l); break;
-    case 1: arg = tcopy(argv[0]); break;
-    default: return duperror(&result, usage);
-  }
-  switch (arg.type) {
-  case INT: return arg;
-  case FLOAT: return arg;
-  case BOOL: if (arg.u.bl) result.u.integer = 1; /* FALL THROUGH */
-  case EMPTY: return result;
-  case STRING: {
-    char *p = arg.u.string;
-    Token *st = scan_integer(&p);
-    if (st != NULLTOKEN && *p == '\0') result = *st;
-    else {
-      p = arg.u.string;
-      st = scan_flt(&p);
-      if (st == NULLTOKEN || *p != '\0')
-	duperror(&result, _("string does not represent a number"));
-      else result = *st;
-    }
-    free(st);
-    tfree(&arg);
-    return result;
-  }
-  default: break;
-  }
-  tfree(&arg);
-  return duperror(&result, usage);
-}
-/*}}}*/
-
 /* int */ /*{{{*/
 static Token int_func(FunctionIdentifier self, int argc, const Token argv[])
 {
@@ -786,6 +807,47 @@ static Token int_func(FunctionIdentifier self, int argc, const Token argv[])
 }
 /*}}}*/
 
+/* number -- convert to most appropriate number type */ /*{{{*/
+static Token number_func(FunctionIdentifier self, int argc, const Token argv[])
+{
+  assert(self == FUNC_NUMBER);
+  const char *usage = _("Usage: number[([bool|empty|int|float|string x])]");
+  Token result, arg;
+  result.type = INT;
+  result.u.integer = 0;
+
+  switch (argc) {
+    case -1: return self_func(self, argc, argv);
+    case 0: arg = recompvalue(upd_sheet, upd_l); break;
+    case 1: arg = tcopy(argv[0]); break;
+    default: return duperror(&result, usage);
+  }
+  switch (arg.type) {
+  case INT: return arg;
+  case FLOAT: return arg;
+  case BOOL: if (arg.u.bl) result.u.integer = 1; /* FALL THROUGH */
+  case EMPTY: return result;
+  case STRING: {
+    char *p = arg.u.string;
+    Token *st = scan_integer(&p);
+    if (st != NULLTOKEN && *p == '\0') result = *st;
+    else {
+      p = arg.u.string;
+      st = scan_flt(&p);
+      if (st == NULLTOKEN || *p != '\0')
+	duperror(&result, _("string does not represent a number"));
+      else result = *st;
+    }
+    free(st);
+    tfree(&arg);
+    return result;
+  }
+  default: break;
+  }
+  tfree(&arg);
+  return duperror(&result, usage);
+}
+/*}}}*/
 
 /* string */ /*{{{*/
 static Token string_func(FunctionIdentifier self, int argc, const Token argv[])
@@ -972,7 +1034,16 @@ static Token region_func(RegFuncInit init, RegFuncUpdt updt, RegFuncFinl finl,
       Token tmp = recompvalue(upd_sheet, w);
       updt(id, &l, &t, &w, &tmp);
       tfree_protected(&tmp, t);
-      if (t.type == EEK) return t;
+      if (t.type == EEK) {
+        const char *templ = _("While computing %s() at &(%d,%d,%d): %s");
+	Token report;
+	report.type = EEK;
+	report.u.err =
+	  malloc(strlen(templ) + MAX_FUNC_NAME_LENGTH + 3*20 + strlen(t.u.err));
+	sprintf(report.u.err, templ, tfunc[id].name, w[X], w[Y], w[Z], t.u.err);
+	tfree(&t);
+	return report;
+      }
     }
     if (finl != (RegFuncFinl)0) finl(id, &l, &t);
     return t;
@@ -1539,21 +1610,22 @@ Tfunc tfunc[]=
  [FUNC_CARET]         = { "^",      accum_func,  INFIX_POW,  FUNCT, 0 },
 
  /* Addressing/cell fetching/cell-position functions */
- [FUNC_AMPERSAND]   = { "&",     adr_func,  PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_AMPERSAND]   = { "&",     adr_func,   PREFIX_FUNC, FUNCT, 0 },
- [FUNC_D]           = { "D",     adr_func,  PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_D]           = { "D",     adr_func,   PREFIX_FUNC, FUNCT, 0 },
- [FUNC_X_AMPERSAND] = { "X&",    adr_func,  PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_X_AMPERSAND] = { "X&",    adr_func,   PREFIX_FUNC, FUNCT, 0 },
- [FUNC_AT_SYMBOL]   = { "@",     at_func,   PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_AT_SYMBOL]   = { "@",     at_func,    PREFIX_FUNC, FUNCT, 0 },
- [FUNC_R]           = { "R",     at_func,   PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_R]           = { "R",     at_func,    PREFIX_FUNC, FUNCT, 0 },
- [FUNC_CAP_X]       = { "X",     at_func,   PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_CAP_X]       = { "X",     at_func,    PREFIX_FUNC, FUNCT, 0 },
- [FUNC_RIGHT]       = { "right", disp_func, PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_RIGHT]       = { "right", disp_func,  PREFIX_FUNC, FUNCT, 0 },
- [FUNC_LEFT]        = { "left",  disp_func, PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_LEFT]        = { "left",  disp_func,  PREFIX_FUNC, FUNCT, 0 },
- [FUNC_DOWN]        = { "down",  disp_func, PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_DOWN]        = { "down",  disp_func,  PREFIX_FUNC, FUNCT, 0 },
- [FUNC_UP]          = { "up",    disp_func, PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_UP]          = { "up",    disp_func,  PREFIX_FUNC, FUNCT, 0 },
- [FUNC_BELOW]       = { "below", disp_func, PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_BELOW]       = { "below", disp_func,  PREFIX_FUNC, FUNCT, 0 },
- [FUNC_ABOVE]       = { "above", disp_func, PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_ABOVE]       = { "above", disp_func,  PREFIX_FUNC, FUNCT, 0 },
- [FUNC_X]           = { "x",     dim_func,  PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_X]           = { "x",     dim_func,   PREFIX_FUNC, FUNCT, 0 },
- [FUNC_Y]           = { "y",     dim_func,  PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_Y]           = { "y",     dim_func,   PREFIX_FUNC, FUNCT, 0 },
- [FUNC_Z]           = { "z",     dim_func,  PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_Z]           = { "z",     dim_func,   PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_FIND]        = { "find",  find_macro, PREFIX_FUNC, MACRO, 0 },
 
  /* Evaluation control functions */
  [FUNC_CLOCK] = { "clock", clock_func, PREFIX_FUNC, FUNCT, 0 },
@@ -1566,7 +1638,7 @@ Tfunc tfunc[]=
  [FUNC_TRUE]  = { "true",  blcnst_func, PREFIX_FUNC, FUNCT, 0 },
 
  /* Type conversion/testing functions and keywords */
- [FUNC_BOOL]     = { "bool",     self_func,   PREFIX_FUNC, FUNCT, 0 },
+ [FUNC_BOOL]     = { "bool",     bool_func,   PREFIX_FUNC, FUNCT, 0 },
  [FUNC_EMPTY]    = { "empty",    empty_func,  PREFIX_FUNC, FUNCT, 0 },
  [FUNC_ERROR]    = { "error",    error_func,  PREFIX_FUNC, FUNCT, 0 },
  [FUNC_FIDENT]   = { "fident",   self_func,   PREFIX_FUNC, FUNCT, 0 },

src/common/func.h

@@ -37,7 +37,7 @@ typedef enum
  FUNC_BOOL, FUNC_EMPTY, FUNC_FIDENT,
  FUNC_FUNCALL, FUNC_LIDENT, FUNC_LOCATION, FUNC_NUMBER, FUNC_OPERATOR,
 
- FUNC_IS,
+ FUNC_IS, FUNC_FIND,
 
  N_FUNCTION_IDS
 } FunctionIdentifier;

src/common/scanner.c

@@ -133,15 +133,19 @@ static Token *charstring(char **s)
 Token *scan_integer(char **s)
 {
   char *r = *s;
+  bool ishex = (*s)[0] == '0' && (*s)[1] == 'x';
   IntT i = STRTOINT(r, s, 0);
-  if (*s != r && **s != '.' && **s != 'e')
+  if (*s == r
-  {
+      || **s == '.' || **s == 'e' || **s == 'E' || (ishex && **s == 'p'))
-    Token *n = malloc(sizeof(Token));
+  { /* either doesn't look like a number, or looks like a float, not an int */
-    n->type = INT;
+    *s = r;
-    n->u.integer = i;
+    return NULLTOKEN;
-    return n;
   }
-  else { *s = r; return NULLTOKEN; }
+  /* looks like an int */
+  Token *n = malloc(sizeof(Token));
+  n->type = INT;
+  n->u.integer = i;
+  return n;
 }
 /*}}}*/
 

src/common/sheet.c

@@ -611,6 +611,22 @@ Token recompvalue(Sheet *sheet, const Location at)
 }
 /*}}}*/
 
+/* evaluate_at   -- evaluate a token in a sheet at a location */ /*{{{*/
+Token evaluate_at(Token t, Sheet *sheet, const Location at)
+{
+  assert(sheet != (Sheet *)0);
+  Sheet *oldsheet = upd_sheet;
+  upd_sheet = sheet;
+  Location old_l;
+  LOCATION_GETS(old_l, upd_l);
+  LOCATION_GETS(upd_l, at);
+  Token result = evaltoken(t, FULL);
+  LOCATION_GETS(upd_l, old_l);
+  upd_sheet = oldsheet;
+  return result;
+}
+/*}}}*/
+
 /* update        -- update all cells that need it */ /*{{{*/
 void update(Sheet *sheet)
 {

src/common/sheet.h

@@ -91,6 +91,7 @@ bool setwidth(Sheet *sheet, int x, int z, int width);
 int cellwidth(Sheet *sheet, const Location at);
 void puttok(Sheet *sheet, const Location at, Token t, TokVariety v);
 Token recompvalue(Sheet *sheet, const Location at);
+Token evaluate_at(Token t, Sheet *sheet, const Location at);
 void update(Sheet *sheet);
 char *geterror(Sheet *sheet, const Location at);
 void printvalue(char *s, size_t size, size_t chars, StringFormat sf,