• BCS (34/34) Jan 04 2007 This is a totaly template based system. No external utilities are
• Chris Nicholson-Sauls (4/51) Jan 04 2007 Quite impressive! Find a way to implement optional/repeated items, and ...
• BCS (7/18) Jan 04 2007 Thank you
• Don Clugston (33/35) Jan 05 2007 [snip]
• BCS (2/42) Jan 05 2007

BCS <BCS pathlink.com> writes:

This is a totaly template based system. No external utilities are 
needed. (* the 137 loc is after removal of all unneeded line)

Here is a slightly compressed use case:

struct set
{
/******* action code ********/
static PObject Action(char[] string : "MULTIPLY")(PObject[3] set)
    {...}
static PObject Action(char[] string : "SUM"     )(PObject[3] set)
    {...}
static PObject Action(char[] string : "PASS"    )(PObject[1] set)
    {...}

/******** Terminal code *********/
static PObject Terminal(char[] name : "NUM")(IParser p)  {...}
static PObject Terminal(char[] name : "PLUS")(IParser p) {...}
static PObject Terminal(char[] name : "TIMES")(IParser p){...}

// "ADD" indecates the root rule

mixin Parser!("ADD",
     "PRIMARY:PASS/NUM;
      MUL:MULTIPLY/PRIMARY TIMES MUL|PASS/PRIMARY;
      ADD:SUM/MUL PLUS ADD|PASS/MUL;");
}

void main()
{
    auto a = new ExpGrammer;
    a.data = "1 + 3 * 4 + 5 * 5 ";

    Value v = cast(Value)set.Parser(a);

    assert(v !is null);
    writef("%d\n", v.value);
}


full example here:

http://www.webpages.uidaho.edu/~shro8822/exp_grammer.d

full code here:

http://www.webpages.uidaho.edu/~shro8822/dparse.d

Chris Nicholson-Sauls <ibisbasenji gmail.com> writes:

BCS wrote:
 This is a totaly template based system. No external utilities are 
 needed. (* the 137 loc is after removal of all unneeded line)
 
 Here is a slightly compressed use case:
 
 struct set
 {
 /******* action code ********/
 static PObject Action(char[] string : "MULTIPLY")(PObject[3] set)
    {...}
 static PObject Action(char[] string : "SUM"     )(PObject[3] set)
    {...}
 static PObject Action(char[] string : "PASS"    )(PObject[1] set)
    {...}
 
 /******** Terminal code *********/
 static PObject Terminal(char[] name : "NUM")(IParser p)  {...}
 static PObject Terminal(char[] name : "PLUS")(IParser p) {...}
 static PObject Terminal(char[] name : "TIMES")(IParser p){...}
 
 // "ADD" indecates the root rule
 
 mixin Parser!("ADD",
     "PRIMARY:PASS/NUM;
      MUL:MULTIPLY/PRIMARY TIMES MUL|PASS/PRIMARY;
      ADD:SUM/MUL PLUS ADD|PASS/MUL;");
 }
 
 void main()
 {
    auto a = new ExpGrammer;
    a.data = "1 + 3 * 4 + 5 * 5 ";
 
    Value v = cast(Value)set.Parser(a);
 
    assert(v !is null);
    writef("%d\n", v.value);
 }
 
 
 full example here:
 
 http://www.webpages.uidaho.edu/~shro8822/exp_grammer.d
 
 full code here:
 
 http://www.webpages.uidaho.edu/~shro8822/dparse.d

Quite impressive!  Find a way to implement optional/repeated items, and
grouping, and 
you've got one heck of a tool there.  (It's useful now, mind you, for simple
grammars.)

-- Chris Nicholson-Sauls

BCS <nothing pathlink.com> writes:

Chris Nicholson-Sauls wrote:
 BCS wrote:
 This is a totaly template based system. No external utilities are 
 needed. (* the 137 loc is after removal of all unneeded line)


[...]
 
 Quite impressive! 

Thank you

 Find a way to implement optional/repeated items, and 
 grouping, and you've got one heck of a tool there.  (It's useful now, 
 mind you, for simple grammars.)
 
 -- Chris Nicholson-Sauls

Yah, it sort of like a Turing machine. It can do any context free 
grammar (I think) but some are a bit harder. One advantage of skipping 
optional/repeated items is it make the Action rules easier for the user 
  to define.

Don Clugston <dac nospam.com.au> writes:

BCS wrote:
 This is a totaly template based system. No external utilities are 
 needed. (* the 137 loc is after removal of all unneeded line)

[snip]

A beautiful piece of work.
The use of default template value arguments to distinguish actions is an 
act of genius.

Incidentally, the technique can be used for classes as well, allowing 
you to instantiate a class from a string literal.
There's lots of potential here.
---
class ReflectableObject(char [] reflectionName) {
     static assert(0, "Undeclared class");
}

class ReflectableObject(char [] reflectionName : "Animal") {
   int numberOfLegs;
}

class ReflectableObject(char [] reflectionName : "Dog") : 
ReflectableObject!("Animal") {
  int dog;
}

class ReflectableObject(char [] reflectionName : "Cat") : 
ReflectableObject!("Animal")  {
  int cat;
}


void main()
{
    auto x = new ReflectableObject!("Dog");
    x.numberOfLegs=7;
    x.dog = 53;

// OK: animal is a base class of Dog.
   ReflectableObject!("Animal") y = x;

   // Won't compile, because a Dog isn't a Cat.
   ReflectableObject!("Cat") z = x;
}

BCS <nothing pathlink.com> writes:

Don Clugston wrote:
 
 A beautiful piece of work.
 The use of default template value arguments to distinguish actions is an 
 act of genius.
 
 Incidentally, the technique can be used for classes as well, allowing 
 you to instantiate a class from a string literal.
 There's lots of potential here.

SWEET!!!

 ---
 class ReflectableObject(char [] reflectionName) {
     static assert(0, "Undeclared class");
 }
 
 class ReflectableObject(char [] reflectionName : "Animal") {
   int numberOfLegs;
 }
 
 class ReflectableObject(char [] reflectionName : "Dog") : 
 ReflectableObject!("Animal") {
  int dog;
 }
 
 class ReflectableObject(char [] reflectionName : "Cat") : 
 ReflectableObject!("Animal")  {
  int cat;
 }
 
 
 void main()
 {
    auto x = new ReflectableObject!("Dog");
    x.numberOfLegs=7;
    x.dog = 53;
 
 // OK: animal is a base class of Dog.
   ReflectableObject!("Animal") y = x;
 
   // Won't compile, because a Dog isn't a Cat.
   ReflectableObject!("Cat") z = x;
 }