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transition to l2

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Mark Thom
2017-02-21 00:31:04 -07:00
parent 0c17344afe
commit 1b5f8a1db2
12 changed files with 3187 additions and 75 deletions
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README.md
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@@ -8,55 +8,70 @@ pure Prolog.
## Progress
The language L1 is implemented as a simple REPL. It supports
unification on facts and queries without backtracking and rules
without clauses, in the familiar Prolog syntax. No data types apart
from atoms are currently supported.
The language L2 is implemented as a simple REPL. It supports
unification on queries without backtracking, where rules and facts are
limited to a single name/arity pairing, in the familiar Prolog
syntax. No data types apart from atoms are currently supported.
An example of the level of interaction currently supported is:
```
l1> p(Z, Z).
l1> ?- p(Z, Z).
l2> p(Z, Z).
l2> ?- p(Z, Z).
yes
l1> ?- p(Z, z).
l2> ?- p(Z, z).
yes
l1> ?- p(Z, w).
l2> ?- p(Z, w).
yes
l1> clouds(are, nice).
l1> ?- p(z, w).
l2> clouds(are, nice).
l2> ?- p(z, w).
no
l1> ?- p(w, w).
l2> ?- p(w, w).
yes
l1> ?- clouds(Z, Z).
l2> ?- clouds(Z, Z).
no
l1> ?- clouds(Z, W).
l2> ?- clouds(Z, W).
yes
l1> ?- clouds(are, W).
l2> ?- clouds(are, W).
yes
l1> ?- clouds(W, nice).
l2> ?- clouds(W, nice).
yes
l1> ?- clouds(nice, are).
l2> ?- clouds(nice, are).
no
l1> ?- p(Z, h(Z, W), f(W)).
l2> ?- p(Z, h(Z, W), f(W)).
no
l1> p(Z, h(Z, W), f(W)).
l1> ?- p(z, h(z, z), f(w)).
l2> p(Z, h(Z, W), f(W)).
l2> ?- p(z, h(z, z), f(w)).
no
l1> ?- p(z, h(z, w), f(w)).
l2> ?- p(z, h(z, w), f(w)).
yes
l1> ?- p(Z, h(z, W), f(w)).
l2> ?- p(Z, h(z, W), f(w)).
yes
l1> ?- p(z, h(Z, w), f(w)).
l2> ?- p(z, h(Z, w), f(w)).
yes
l1> ?- p(Z, h(Z, w), f(Z)).
l2> ?- p(Z, h(Z, w), f(Z)).
yes
l1> ?- p(z, h(Z, w), f(Z)).
l2> ?- p(z, h(Z, w), f(Z)).
no
l1> p(f(X), h(Y, f(a)), Y).
l1> ?- p(Z, h(Z, W), f(W)).
l2> p(f(X), h(Y, f(a)), Y).
l2> ?- p(Z, h(Z, W), f(W)).
yes
l1> quit
l2> p(X, Y) :- q(X, Z), r(Z, Y).
l2> q(q, s).
l2> r(s, t).
l2> ?- p(X, Y).
yes
l2> ?- p(q, t).
yes
l2> ?- p(t, q).
no
l2> ?- p(q, T).
yes
l2> ?- p(Q, t).
yes
l2> ?- p(t, t).
no
l2> quit
```
## Occurs check
@@ -64,7 +79,7 @@ l1> quit
There's no occurs check, so cyclic terms do unify:
```
l1> p(W, W).
l1> ?- p(f(f(W)), W).
l2> p(W, W).
l2> ?- p(f(f(W)), W).
yes
```