diff --git a/include/semver.h b/include/semver.h
index 18a9d3c..4e573e5 100644
--- a/include/semver.h
+++ b/include/semver.h
@@ -1,7 +1,8 @@
 #include "epoch.h"
 #include <stdint.h>
 
-#define u128 __uint128_t
+#define u128    __uint128_t
+#define U12_MAX 4096
 
 typedef enum {
     Simple,
diff --git a/semver.c b/semver.c
index ac3ee98..3b07e97 100644
--- a/semver.c
+++ b/semver.c
@@ -106,9 +106,69 @@ int parseArch(char *s) {
         return -1;
 }
 
-int parsePreRelease(PreRelease *pr, const char *s) {
+uint16_t parseNumNonZero(char *vp, long *out) {
+    long val;
+    char *ep;
+
+    if (vp  == NULL) {
+        *out = 0;
+    }
+    val = strtol(vp, &ep, 10);
+    if (vp != ep && ep == NULL && val <= U12_MAX) {
+        *out = val;
+    } else {
+        return 1;
+    }
+    return 0;
+}
+
+int parseGitRev(char *vp, GitRevision *git) {
     // todo
-    return -1;
+    return 1;
+}
+
+int parsePreRelease(PreRelease *pr, char *s) {
+    PreReleaseTag tag;
+    long          val = 0;
+    char         *vp;
+
+    if (strncasecmp(s, "alpha", 5) == 0) {
+        tag = Alpha;
+        vp = s + 5;
+        if (parseNumNonZero(vp, &val) != 0)
+            return  1;
+    } else if (strncasecmp(s, "beta", 4) == 0) {
+        tag = Beta;
+        vp = s + 4;
+        if (parseNumNonZero(vp, &val) != 0)
+            return 1;
+    } else if (strncasecmp(s, "rc", 2) == 0) {
+        tag = ReleaseCandidate;
+        vp = s + 2;
+        if (parseNumNonZero(vp, &val) != 0)
+            return 1;
+    } else if (strncasecmp(s, "git_", 4) == 0) {
+        tag = GitRev;
+        vp = s + 4;
+        if (parseGitRev(vp, &pr->git) != 0)
+            return 1;
+    }
+    pr->tag = tag;
+    switch (tag) {
+        case Alpha:
+            pr->alpha = (uint16_t)val;
+            break;
+        case Beta:
+            pr->beta = (uint16_t)val;
+            break;
+        case ReleaseCandidate:
+            pr->rc = (uint16_t)val;
+            break;
+        case GitRev:
+            break;
+        default: return -1;
+    }
+    return 0;
 }
 
 int parseVersion(Version *self, const char *s) {
@@ -156,13 +216,22 @@ char *versionToString(Version *self) {
             snprintf(temp, 9, "-%s", archToString(self->arch));
             break;
         case Alpha:
-            snprintf(temp, 25, "_alpha%d-%s", self->pr.alpha, archToString(self->arch));
+            if (self->pr.alpha == 0)
+                snprintf(temp, 25, "_alpha-%s", archToString(self->arch));
+            else
+                snprintf(temp, 25, "_alpha%d-%s", self->pr.alpha, archToString(self->arch));
             break;
         case Beta:
-            snprintf(temp, 25, "_beta%d-%s", self->pr.beta, archToString(self->arch));
+            if (self->pr.beta == 0)
+                snprintf(temp, 25, "_beta-%s", archToString(self->arch));
+            else
+                snprintf(temp, 25, "_beta%d-%s", self->pr.beta, archToString(self->arch));
             break;
         case ReleaseCandidate:
-            snprintf(temp, 25, "_rc%d-%s", self->pr.rc, archToString(self->arch));
+            if (self->pr.rc == 0)
+                snprintf(temp, 25, "_rc-%s", archToString(self->arch));
+            else
+                snprintf(temp, 25, "_rc%d-%s", self->pr.rc, archToString(self->arch));
             break;
         case GitRev:
             snprintf(