diff --git a/src/frontend/vectors.c b/src/frontend/vectors.c
index 3daba86cf..3d26bc95b 100644
--- a/src/frontend/vectors.c
+++ b/src/frontend/vectors.c
@@ -23,6 +23,17 @@ Author: 1985 Wayne A. Christopher, U. C. Berkeley CAD Group
 #include "ngspice/dstring.h"
 #include "plotting/plotting.h"
 
+
+static struct dvec *findvec_all(struct plot *pl);
+static struct dvec *findvec_allv(struct plot *pl);
+static struct dvec *findvec_alli(struct plot *pl);
+static struct dvec *findvec_ally(struct plot *pl);
+static struct dvec *find_permanent_vector_by_name(
+        NGHASHPTR pl_lookup_table, char *name);
+static enum ALL_TYPE_ENUM get_all_type(const char *word);
+static bool plot_prefix(const char *pre, const char *str);
+
+
 #ifdef XSPICE
 /* gtri - begin - add function prototype for EVTfindvec */
 struct dvec *EVTfindvec(char *node);
@@ -30,8 +41,7 @@ struct dvec *EVTfindvec(char *node);
 #endif
 
 
-static void
-vec_rebuild_lookup_table(struct plot *pl)
+static void vec_rebuild_lookup_table(struct plot *pl)
 {
     if (pl->pl_lookup_table) { /* existing table */
         nghash_empty(pl->pl_lookup_table, NULL, NULL);
@@ -63,112 +73,107 @@ vec_rebuild_lookup_table(struct plot *pl)
         ds_free(&dbuf);
     }
 
-    pl->pl_lookup_valid = TRUE;
+    pl->pl_lookup_valid = TRUE; /* now lookup table valid */
 } /* end of function vec_rebuild_lookup_table */
 
 
 
+enum ALL_TYPE_ENUM {
+    ALL_TYPE_NONE,
+    ALL_TYPE_ALL,
+    ALL_TYPE_ALLV,
+    ALL_TYPE_ALLI,
+    ALL_TYPE_ALLY
+};
+
+
+/* Efficient identification of "all", "allv", "alli", "ally", and anything
+ * else */
+static enum ALL_TYPE_ENUM get_all_type(const char *word)
+{
+    /* Check for start of "all" */
+    if (tolower(word[0] != 'a')) {
+        return ALL_TYPE_NONE;
+    }
+    if (tolower(word[1] != 'l')) {
+        return ALL_TYPE_NONE;
+    }
+    if (tolower(word[2] != 'l')) {
+        return ALL_TYPE_NONE;
+    }
+
+    /* It may be some type of all */
+    switch (tolower(word[3])) {
+    case '\0':
+        return ALL_TYPE_ALL;
+    case 'v':
+        if (word[4] == '\0') {
+            return ALL_TYPE_ALLV;
+        }
+        else {
+            return ALL_TYPE_NONE;
+        }
+    case 'i':
+        if (word[4] == '\0') {
+            return ALL_TYPE_ALLI;
+        }
+        else {
+            return ALL_TYPE_NONE;
+        }
+    case 'y':
+        if (word[4] == '\0') {
+            return ALL_TYPE_ALLY;
+        }
+        else {
+            return ALL_TYPE_NONE;
+        }
+    default:
+        return ALL_TYPE_NONE;
+    } /* end of swith over char after "all" */
+} /* end of function get_all_type */
+
+
+
 /* Find a named vector in a plot. We are careful to copy the vector if
  * v_link2 is set, because otherwise we will get screwed up.  */
-static struct dvec *
-findvec(char *word, struct plot *pl) {
-    struct dvec *d, *newv = NULL, *end = NULL, *v;
-
-    if (pl == NULL)
-        return (NULL);
-
-    if (cieq(word, "all")) {
-        for (d = pl->pl_dvecs; d; d = d->v_next) {
-            if (d->v_flags & VF_PERMANENT) {
-                if (d->v_link2) {
-                    v = vec_copy(d);
-                    vec_new(v);
-                } else {
-                    v = d;
-                }
-                if (end)
-                    end->v_link2 = v;
-                else
-                    newv = v;
-                end = v;
-            }
-        }
-        return (newv);
+static struct dvec *findvec(char *word, struct plot *pl)
+{
+    /* If no plot, cannot find */
+    if (pl == NULL) {
+        return NULL;
     }
 
-    if (cieq(word, "allv")) {
-        for (d = pl->pl_dvecs; d; d = d->v_next) {
-            if ((d->v_flags & VF_PERMANENT) && (d->v_type == SV_VOLTAGE)) {
-                if (d->v_link2) {
-                    v = vec_copy(d);
-                    vec_new(v);
-                } else {
-                    v = d;
-                }
-                if (end)
-                    end->v_link2 = v;
-                else
-                    newv = v;
-                end = v;
-            }
-        }
-        return (newv);
+    /* Identify and handle special cases all, allv, alli, ally */
+    switch (get_all_type(word)) {
+    case ALL_TYPE_ALL:
+        return findvec_all(pl);
+    case ALL_TYPE_ALLV:
+        return findvec_allv(pl);
+    case ALL_TYPE_ALLI:
+        return findvec_alli(pl);
+    case ALL_TYPE_ALLY:
+        return findvec_ally(pl);
+    default: /* case ALL_TYPE_NOT_ALL -- not some type of ALL */
+        break;
     }
 
-    if (cieq(word, "alli")) {
-        for (d = pl->pl_dvecs; d; d = d->v_next) {
-            if ((d->v_flags & VF_PERMANENT) && (d->v_type == SV_CURRENT)) {
-                if (d->v_link2) {
-                    v = vec_copy(d);
-                    vec_new(v);
-                } else {
-                    v = d;
-                }
-                if (end)
-                    end->v_link2 = v;
-                else
-                    newv = v;
-                end = v;
-            }
-        }
-        return (newv);
-    }
-
-    if (cieq(word, "ally")) {
-        for (d = pl->pl_dvecs; d; d = d->v_next) {
-            if ((d->v_flags & VF_PERMANENT) && (!cieq(d->v_name, pl->pl_scale->v_name))) {
-                if (d->v_link2) {
-                    v = vec_copy(d);
-                    vec_new(v);
-                } else {
-                    v = d;
-                }
-                if (end)
-                    end->v_link2 = v;
-                else
-                    newv = v;
-                end = v;
-            }
-        }
-        return (newv);
-    }
-
-    if (!pl->pl_lookup_valid)
+    /* The find is not for one of the "all" cases */
+    if (!pl->pl_lookup_valid) {
+        /* Table lookup not valid, so rebuild to make valid */
         vec_rebuild_lookup_table(pl);
+    }
 
     DS_CREATE(dbuf, 200); /* make dynamic buffer */
     if (ds_cat_str_case(&dbuf, word, ds_case_lower) != DS_E_OK) {
         controlled_exit(-1);
     }
     char * const lower_name = ds_get_buf(&dbuf);
+    NGHASHPTR pl_lookup_table = pl->pl_lookup_table;
+    struct dvec *d = find_permanent_vector_by_name(pl_lookup_table,
+            lower_name);
 
-    for (d = nghash_find(pl->pl_lookup_table, lower_name);
-            d;
-            d = nghash_find_again(pl->pl_lookup_table, lower_name)) {
-        if (d->v_flags & VF_PERMANENT)
-            break;
-    }
-
+    /* If the vector was not using the lowercased name, try finding it as
+     * v(lowercased name) */
     if (!d) {
         ds_clear(&dbuf);
         bool f_ok = ds_cat_str(&dbuf, "v(") == DS_E_OK;
@@ -179,12 +184,7 @@ findvec(char *word, struct plot *pl) {
             controlled_exit(-1);
         }
         char * const node_name = ds_get_buf(&dbuf);
-        for (d = nghash_find(pl->pl_lookup_table, node_name);
-                d;
-                d = nghash_find_again(pl->pl_lookup_table, node_name)) {
-            if (d->v_flags & VF_PERMANENT)
-                break;
-        }
+        d = find_permanent_vector_by_name(pl_lookup_table, node_name);
     }
 
     ds_free(&dbuf);
@@ -192,8 +192,9 @@ findvec(char *word, struct plot *pl) {
 #ifdef XSPICE
     /* gtri - begin - Add processing for getting event-driven vector */
 
-    if (!d)
+    if (!d) {
         d = EVTfindvec(word);
+    }
 
     /* gtri - end   - Add processing for getting event-driven vector */
 #endif
@@ -207,11 +208,72 @@ findvec(char *word, struct plot *pl) {
 
 
 
+/* Macro taking a function name and vector filter as arguments that
+ * generates the function that applies the filter */
+#define FINDVEC_ALL_GEN(fun_name, filter)\
+static struct dvec *fun_name(struct plot *pl)\
+{\
+    struct dvec *d, *newv = NULL, *end = NULL, *v;\
+    for (d = pl->pl_dvecs; d; d = d->v_next) {\
+        if (filter) {\
+            if (d->v_link2) {\
+                v = vec_copy(d);\
+                vec_new(v);\
+            }\
+            else {\
+                v = d;\
+            }\
+            if (end) {\
+                end->v_link2 = v;\
+            }\
+            else {\
+                newv = v;\
+            }\
+            end = v;\
+        }\
+    } /* end of loop over vectors in plot */\
+\
+    return newv;\
+} /* end of function */
+
+/* Generate the functions for each filter */
+FINDVEC_ALL_GEN(findvec_all, d->v_flags & VF_PERMANENT)
+FINDVEC_ALL_GEN(findvec_allv,
+        (d->v_flags & VF_PERMANENT) && (d->v_type == SV_VOLTAGE))
+FINDVEC_ALL_GEN(findvec_alli,
+        (d->v_flags & VF_PERMANENT) && (d->v_type == SV_CURRENT))
+FINDVEC_ALL_GEN(findvec_ally,
+        (d->v_flags & VF_PERMANENT) &&
+                (!cieq(d->v_name, pl->pl_scale->v_name)))
+
+
+
+/* Find a permanent vector with the given name */
+static struct dvec *find_permanent_vector_by_name(
+        NGHASHPTR pl_lookup_table, char *name)
+{
+    struct dvec *d;
+
+    /* Find the first vector with the given name and then find others
+     * until one having the VF_PERMANENT flag set is found. */
+    for (d = nghash_find(pl_lookup_table, name);
+            d;
+            d = nghash_find_again(pl_lookup_table, name)) {
+        if (d->v_flags & VF_PERMANENT) {
+            /* A "permanent" vector was found with the name, so done */
+            return d;
+        }
+    } /* end of loop over vectors in the plot having this name */
+
+    return (struct dvec *) NULL; /* not found */
+} /* end of function find_permanent_vector_by_name */
+
+
+
 /* If there are imbedded numeric strings, compare them numerically, not
  * alphabetically.
  */
-static int
-namecmp(const void *a, const void *b)
+static int namecmp(const void *a, const void *b)
 {
     int i, j;
 
@@ -373,38 +435,44 @@ vec_remove(const char *name)
  * it checks for pre-defined vectors.
  */
 
-struct dvec *
-vec_fromplot(char *word, struct plot *plot) {
-    struct dvec *d;
-    char buf[BSIZE_SP], buf2[BSIZE_SP], cc, *s;
-
-    d = findvec(word, plot);
-    if (!d) {
-        (void) strcpy(buf, word);
-        strtolower(buf);
-        d = findvec(buf, plot);
-    }
-    if (!d) {
-        (void) strcpy(buf, word);
-        strtoupper(buf);
-        d = findvec(buf, plot);
+struct dvec *vec_fromplot(char *word, struct plot *plot) {
+    struct dvec *d = findvec(word, plot);
+    if (d != (struct dvec *) NULL) {
+        return d;
     }
 
-    /* scanf("%c(%s)" doesn't do what it should do. ) */
-    if (!d && (sscanf(word, "%c(%s", &cc, buf) == 2) &&
-            ((s = strrchr(buf, ')')) != NULL) &&
-            (s[1] == '\0')) {
-        *s = '\0';
-        if (prefix("i(", word) || prefix("I(", word)) {
-            /* Spice dependency... */
-            (void) sprintf(buf2, "%s#branch", buf);
-            (void) strcpy(buf, buf2);
+    /* Consider forms I(node) and i(node) -> node#branch */
+    if (tolower(word[0]) != (int) 'i') { /* Not i of I.* */
+        return (struct dvec *) NULL;
+    }
+
+    if (word[1] != '(') { /* Not i or I(.* */
+        return (struct dvec *) NULL;
+    }
+
+    {
+        const char * const p_node = word + 2;
+        const char *p_end = p_node + strlen(p_node);
+        if (*--p_end != ')') { /* Not i or I then '(' with a closing ')' */
+            return (struct dvec *) NULL;
         }
-        d = findvec(buf, plot);
-    }
 
-    return (d);
-}
+        /* Form is correct, so see if node#branch exists */
+        DS_CREATE(ds, 100);
+        if (ds_cat_mem(&ds, p_node, p_end - p_node) != DS_E_OK) {
+            controlled_exit(-1);
+        }
+        if (ds_cat_str(&ds, "#branch") != DS_E_OK) {
+            controlled_exit(-1);
+        }
+
+        d = findvec(ds_get_buf(&ds), plot);
+        ds_free(&ds);
+
+        return d;
+    }
+} /* end of function vec_fromplot */
+
 
 
 /* This is the main lookup routine for names. The possible types of names are:
@@ -484,7 +552,7 @@ vec_get(const char *vec_name) {
         }
     }
 
-    if (!d && (*word == SPECCHAR)) {
+    if (!d && (*word == SPECCHAR)) { /* "@" */
         /* This is a special quantity... */
         if (ft_nutmeg) {
             fprintf(cp_err,
@@ -579,30 +647,37 @@ vec_get(const char *vec_name) {
              */
             struct variable *nv;
 
+            /* Count the number of nodes in the list */
             i = 0;
-            for (nv = vv->va_vlist; nv; nv = nv->va_next)
+            for (nv = vv->va_vlist; nv; nv = nv->va_next) {
                 i++;
+            }
 
-            dvec_realloc(d, i, NULL);
+            dvec_realloc(d, i, NULL); /* Resize to # nodes */
 
+            /* Step through the list again, setting values this time */
             i = 0;
-            for (nv = vv->va_vlist; nv; nv = nv->va_next)
+            for (nv = vv->va_vlist; nv; nv = nv->va_next) {
                 d->v_realdata[i++] = nv->va_real;
+            }
 
             /* To be able to identify the vector to represent
              * belongs to a special "conunto" and should be printed in a
              * special way.
              */
             d->v_dims[1] = 1;
-        } else if (vv->va_type == CP_NUM) { /* Variable is an integer */
+        }
+        else if (vv->va_type == CP_NUM) { /* Variable is an integer */
             *d->v_realdata = (double) vv->va_num;
-        } else if (vv->va_type == CP_REAL) { /* Variable is a real */
+        }
+        else if (vv->va_type == CP_REAL) { /* Variable is a real */
             if (!(vv->va_next)) {
                 /* Only a real data
                  * usually normal
                  */
                 *d->v_realdata = vv->va_real;
-            } else {
+            }
+            else {
                 /* Real data set
                  * When you print a model @ [all]
                  * Just print numerical values, not the string
@@ -632,8 +707,9 @@ vec_get(const char *vec_name) {
                     }
                     nv = nv->va_next;
 
-                    if (!nv)
+                    if (!nv) {
                         break;
+                    }
                 }
 
                 /* To distinguish those does not take anything for print screen to
@@ -648,7 +724,7 @@ vec_get(const char *vec_name) {
         tfree(wd);
         vec_new(d);
         tfree(whole);
-        return (d);
+        return d;
     }
 
     tfree(wd);
@@ -676,27 +752,29 @@ plot_docoms(wordlist *wl)
 }
 
 
-/* Create a copy of a vector. */
-
-struct dvec *
-vec_copy(struct dvec *v) {
+/* Create a copy of a vector. The vector is not "permananent" */
+struct dvec *vec_copy(struct dvec *v) {
     struct dvec *nv;
-    int i;
 
-    if (!v)
-        return (NULL);
+    if (!v) {
+        return (struct dvec *) NULL;
+    }
 
+    /* Make a copy with the VF_PERMANENT bit cleared in v_flags */
     nv = dvec_alloc(copy(v->v_name),
                     v->v_type,
                     v->v_flags & ~VF_PERMANENT,
                     v->v_length, NULL);
 
-    if (isreal(v))
-        memcpy(nv->v_realdata, v->v_realdata,
+    /* Copy the data to the new vector */
+    if (isreal(v)) {
+        (void) memcpy(nv->v_realdata, v->v_realdata,
                sizeof(double) * (size_t) v->v_length);
-    else
-        memcpy(nv->v_compdata, v->v_compdata,
+    }
+    else {
+        (void) memcpy(nv->v_compdata, v->v_compdata,
                sizeof(ngcomplex_t) * (size_t) v->v_length);
+    }
 
     nv->v_minsignal = v->v_minsignal;
     nv->v_maxsignal = v->v_maxsignal;
@@ -719,23 +797,26 @@ vec_copy(struct dvec *v) {
     nv->v_color = 0; /*XXX???*/
     nv->v_defcolor = v->v_defcolor;
     nv->v_numdims = v->v_numdims;
-    for (i = 0; i < v->v_numdims; i++)
-        nv->v_dims[i] = v->v_dims[i];
+
+    /* Copy defined dimensions */
+    (void) memcpy(nv->v_dims, v->v_dims, v->v_numdims * sizeof *v->v_dims);
+
     nv->v_plot = v->v_plot;
     nv->v_next = NULL;
     nv->v_link2 = NULL;
     nv->v_scale = v->v_scale;
 
-    return (nv);
-}
+    return nv;
+} /* end of function vec_copy */
+
 
 
 /* Create a new plot structure. This just fills in the typename and sets up
  * the ccom struct.
  */
 
-struct plot *
-plot_alloc(char *name) {
+struct plot * plot_alloc(char *name)
+{
     struct plot *pl = TMALLOC(struct plot, 1), *tp;
     char *s;
     struct ccom *ccom;
@@ -841,71 +922,93 @@ vec_gc(void)
  * in a plot are gone it stays around...
  */
 
-void
-vec_free_x(struct dvec *v)
+void vec_free_x(struct dvec *v)
 {
-    struct plot *pl;
-
-    if ((v == NULL) || (v->v_name == NULL))
+    /* Do not free if NULL or name is NULL. The second possibility is a
+     * special case */
+    if ((v == NULL) || (v->v_name == NULL)) {
         return;
-    pl = v->v_plot;
+    }
+    struct plot * const pl = v->v_plot;
 
     /* Now we have to take this dvec out of the plot list. */
     if (pl != NULL) {
         pl->pl_lookup_valid = FALSE;
+
+        /* If at head of list of vectors in the plot, make the next one
+         * the new head of the list */
         if (pl->pl_dvecs == v) {
             pl->pl_dvecs = v->v_next;
-        } else {
+        }
+        else {
+            /* Not at head of list so must locate and fix links */
             struct dvec *lv = pl->pl_dvecs;
-            if (lv)
-                for (; lv->v_next; lv = lv->v_next)
-                    if (lv->v_next == v)
+            if (lv) { /* the plot has at least one vector */
+                for ( ; lv->v_next; lv = lv->v_next) {
+                    if (lv->v_next == v) { /* found prev vector */
                         break;
-            if (lv && lv->v_next)
+                    }
+                }
+            }
+
+            /* If found in the list, link prev vector to next one */
+            if (lv && lv->v_next) {
                 lv->v_next = v->v_next;
-            else
-                fprintf(cp_err,
+            }
+            else {
+                (void) fprintf(cp_err,
                         "vec_free: Internal Error: %s not in plot\n",
                         v->v_name);
-        }
+            }
+        } /* end of case that vector being freed is not at head of list */
+
         if (pl->pl_scale == v) {
-            if (pl->pl_dvecs)
+            if (pl->pl_dvecs) {
                 pl->pl_scale = pl->pl_dvecs;    /* Random one... */
-            else
+            }
+            else {
                 pl->pl_scale = NULL;
+            }
+        }
+    } /* end of case that have a plot */
+
+    dvec_free(v);
+} /* end of function vec_free_x */
+
+
+
+/* This function returns TRUE if every element of v and every element of
+ * every vector linked to v through v_link2 is zero and FALSE otherwise. */
+bool vec_iszero(const struct dvec *v)
+{
+    for (; v; v = v->v_link2) { /* step through linked vectors */
+        if (isreal(v)) { /* current vector is real */
+            const int n = v->v_length;
+            int i;
+            for (i = 0; i < n; i++) {
+                if (v->v_realdata[i] != 0.0) {
+                    return FALSE;
+                }
+            }
+        }
+        else { /* current vector is complex */
+            const int n = v->v_length;
+            int i;
+            for (i = 0; i < n; i++) {
+                if (realpart(v->v_compdata[i]) != 0.0) {
+                    return FALSE;
+                }
+                if (imagpart(v->v_compdata[i]) != 0.0) {
+                    return FALSE;
+                }
+            }
         }
     }
 
-    dvec_free(v);
-}
+    return TRUE; /* every value tested was 0.0 */
+} /* end of function vec_iszero */
 
 
-/*
- * return TRUE if every vector element is zero
- */
-
-bool
-vec_iszero(struct dvec *v)
-{
-    int i;
-
-    for (; v; v = v->v_link2)
-        if (isreal(v))
-            for (i = 0; i < v->v_length; i++) {
-                if (v->v_realdata[i] != 0.0)
-                    return FALSE;
-            }
-        else
-            for (i = 0; i < v->v_length; i++) {
-                if (realpart(v->v_compdata[i]) != 0.0)
-                    return FALSE;
-                if (imagpart(v->v_compdata[i]) != 0.0)
-                    return FALSE;
-            }
-
-    return TRUE;
-}
-
 
 /* This is something we do in a few places...  Since vectors get copied a lot,
  * we can't just compare pointers to tell if two vectors are 'really' the same.
@@ -962,15 +1065,20 @@ vec_basename(struct dvec *v)
 }
 
 /* get address of plot named 'name' */
-struct plot *
-get_plot(char* name) {
+struct plot *get_plot(char* name)
+
+
+{
     struct plot *pl;
-    for (pl = plot_list; pl; pl = pl->pl_next)
-        if (plot_prefix(name, pl->pl_typename))
+    for (pl = plot_list; pl; pl = pl->pl_next) {
+        if (plot_prefix(name, pl->pl_typename)) {
             return pl;
+        }
+    }
     fprintf(cp_err, "Error: no such plot named %s\n", name);
-    return NULL;
-}
+    return (struct plot *) NULL;
+} /* end of function get_plot */
+
 
 
 /* Make a plot the current one.  This gets called by cp_usrset() when one
@@ -1177,16 +1285,16 @@ vec_mkfamily(struct dvec *v) {
 
 
 /* This function will match "op" with "op1", but not "op1" with "op12". */
-
-bool
-plot_prefix(char *pre, char *str)
+static bool plot_prefix(const char *pre, const char *str)
 {
-    if (!*pre)
-        return (TRUE);
+    if (!*pre) { /* prefix is empty string */
+        return TRUE; /* Define "" to be prefix */
+    }
 
     while (*pre && *str) {
-        if (*pre != *str)
+        if (*pre != *str) { /* stop at first mismatch */
             break;
+        }
         pre++;
         str++;
     }
diff --git a/src/include/ngspice/fteext.h b/src/include/ngspice/fteext.h
index 6c35ae118..9a4c9bae0 100644
--- a/src/include/ngspice/fteext.h
+++ b/src/include/ngspice/fteext.h
@@ -336,7 +336,7 @@ extern int ft_typnum(char *);
 
 /* vectors.c */
 
-extern bool vec_iszero(struct dvec *v);
+extern bool vec_iszero(const struct dvec *v);
 extern bool vec_eq(struct dvec *v1, struct dvec *v2);
 extern int plot_num;
 extern struct dvec *vec_fromplot(char *word, struct plot *plot);
@@ -363,7 +363,6 @@ extern void plot_setcur(char *name);
 extern struct plot *get_plot(char* name);
 extern void plot_new(struct plot *pl);
 extern char *vec_basename(struct dvec *v);
-extern bool plot_prefix(char *pre, char *str);
 extern void vec_transpose(struct dvec *v);
 
 /* main.c */