jets: Add +slaw jet which parses %ud and %tas.

Falls back for other types.

pkg/urbit/include/jets/w.h

@@ -116,6 +116,8 @@
     u3_noun u3we_rexp(u3_noun);
     u3_noun u3we_trip(u3_noun);
 
+    u3_noun u3we_slaw(u3_noun);
+
     u3_noun u3we_pfix(u3_noun);
     u3_noun u3we_plug(u3_noun);
     u3_noun u3we_pose(u3_noun);

pkg/urbit/jets/e/slaw.c

@@ -0,0 +1,105 @@
+/* j/3/slaw.c
+**
+*/
+#include "all.h"
+
+#include <ctype.h>
+
+/* functions
+*/
+
+  u3_noun
+  _parse_ud(u3_noun txt) {
+    c3_c* c = u3r_string(txt);
+
+    // First character must represent a digit
+    c3_c* cur = c;
+    if (cur[0] > '9' || cur[0] < '0') {
+      c3_free(c);
+      return 0;
+    }
+    c3_w total = cur[0] - '0';
+    cur++;
+
+    int since_last_period = 0;
+    while (cur[0] != 0) {
+      since_last_period++;
+      if (cur[0] == '.') {
+        since_last_period = 0;
+        cur++;
+        continue;
+      }
+
+      if (cur[0] > '9' || cur[0] < '0') {
+        c3_free(c);
+        return 0;
+      }
+
+      total = u3qa_mul(total, 10);
+      total = u3qa_add(total, cur[0] - '0');
+      cur++;
+
+      if (since_last_period > 3) {
+        c3_free(c);
+        return 0;
+      }
+    }
+
+    c3_free(c);
+    return u3nc(0, total);
+  }
+
+  u3_noun
+  _parse_tas(u3_noun txt) {
+    // For any symbol which matches, txt will return itself as a
+    // value. Therefore, this is mostly checking validity.
+    c3_c* c = u3r_string(txt);
+
+    // First character must represent a lowercase letter
+    c3_c* cur = c;
+    if (!islower(cur[0])) {
+      c3_free(c);
+      return 0;
+    }
+    cur++;
+
+    while (cur[0] != 0) {
+      if (!(islower(cur[0]) || isdigit(cur[0]) || cur[0] == '-')) {
+        c3_free(c);
+        return 0;
+      }
+
+      cur++;
+    }
+
+    c3_free(c);
+    return u3nc(0, txt);
+  }
+
+  u3_noun
+  u3we_slaw(u3_noun cor)
+  {
+    u3_noun mod;
+    u3_noun txt;
+
+    if (c3n == u3r_mean(cor, u3x_sam_2, &mod,
+                        u3x_sam_3, &txt, 0) ||
+        !_(u3a_is_cat(mod))) {
+      return u3m_bail(c3__fail);
+    }
+
+    switch (mod) {
+      /* TODO: case c3__p. Need background jets first. */
+
+      case c3__ud:
+        return _parse_ud(txt);
+
+      // %ta is used once in link.hoon. don't bother.
+
+      case c3__tas:
+        return _parse_tas(txt);
+
+      default:
+        return u3_none;
+    }
+  }

pkg/urbit/jets/tree.c

@@ -607,6 +607,9 @@ static c3_c* _141_qua_trip_ha[] = {
   0
 };
 
+static u3j_harm _141_qua_slaw_a[] = {{".2", u3we_slaw}, {}};
+
+
 static u3j_harm _141_qua__po_ind_a[] = {{".2", u3wcp_ind}, {}};
 static c3_c* _141_qua__po_ind_ha[] = {
   "95bbe9867dbbd1b9ce12671d64cf7b1dee8d987c6770955a83c73291c4537a61",
@@ -883,6 +886,8 @@ static u3j_core _141_qua_d[] =
 
   { "mink", 7, _141_qua_mink_a, 0, _141_qua_mink_ha },
   { "mule", 7, _141_qua_mule_a, 0, _141_qua_mule_ha },
+
+  { "slaw", 7, _141_qua_slaw_a, 0, 0 },
   {}
 };
 static c3_c* _141_qua_ha[] = {