[help-3dldf] Re: Macros in 3DLDF

[Laurence Finston]

Hello Nobre et al,

I've now implemented macros, pretty much as I described them in
my last posting.  However, typed parameters are delimited by (curly)
braces rather than (square) brackets.  Brackets are used for numerical
subscripts, so when I tried to use them for typed arguments in macro
calls, the parser function `yyparse()' shifted the `LEFT_BRACKET' rather
than reducing `symbolic_token' to `variable'.

The following code is an excerpt from `sample0.ldf'.  It contains
examples of how to define and use macros.  It is followed by
the output produced by `3dldf' from this code.

I've uploaded the updated files to Savannah.  I'm about to start
working on rules for defining macros that are elements of
`macro_vectors'.

Laurence

%% *** (3) Examples of using macros.  LDF 2005.01.03.

beginfig(1);

macro a, b, d;  %% Some are declared, others are not.

%% Macro with no arguments.
def a :=
message "This is `a'.";
enddef;

a;

%% Redefining a macro.
def a :=
message "This is `a' after being redefined.";
enddef;

a;

%% A macro with no untyped arguments and a single typed argument.
def b {point c} :=
message "In `b':  `c' == ";
show c;
enddef;

b {(0, 1, 2)};

%% A macro with no typed arguments and a single untyped argument.
def d (e) :=
message "In`d':  `e' == ";
show e;
enddef;

string f;
f := "fff";

d (f);

%% A macro with one typed argument and one untyped argument.
def g (h) {path i} :=
message "In `g':  `h' == ";
show h;
message "In `g':  `i' == ";
show i;
enddef;

point j;

j := (0, 1, 2);

g (j) {origin -- (3, 3, 3)};


%% A nested macro definition.
def k :=
def l :=
message "This is `l' in `k'.";
enddef;
message "This is `k'.";
l;
enddef;

k;

%% A macro with two typed arguments and two untyped arguments.
def m (n, o) {path p, transform q} :=
message "In `m':  `n' == ";
show n;
message "In `m':  `o' == ";
show o;
message "In `m':  `p' == ";
show p;
message "In `m':  `q' == ";
show q;
enddef;

point r;
string s;

r := (0, 1, 2);
s := "sss";

m (r, s) {origin -- (3, 3, 3), identity scaled (1, 2, 3)};

endfig;
end;




*** Output:  ***********************

This is `a'.
This is `a' after being redefined.
In `b':  `c' ==
>> (0.000000, 1.000000, 2.000000)
In`d':  `e' ==
>> fff
In `g':  `h' ==
>> (0.000000, 1.000000, 2.000000)
In `g':  `i' ==
>> Path:
points.size() == 2
connectors.size() == 1
(0.000000, 0.000000, 0.000000) -- (3.000000, 3.000000, 3.000000);
fill_draw_value == 0
draw_color == 0
fill_color == 0
pen == 0
dash_pattern == 0
`arrow' == `Path::NO_ARROW'.

This is `k'.
This is `l' in `k'.
Exiting 3DLDF Version 1.2.0.0.