From 61372b981933236805ad1464b12e138ec7fb7d5d Mon Sep 17 00:00:00 2001
From: lemon <lsof@mailbox.org>
Date: Fri, 7 Feb 2025 17:56:25 +0100
Subject: parser: make read callback be buffered

---
 bench.lua |   2 +-
 pez.c     |  45 +++++++++++++++++++++++++++++++--------------
 pez.h     |   3 ++-
 pez.png   | Bin 0 -> 11408 bytes
 test.pez  |   1 -
 ycomb.pez |   5 +++++
 6 files changed, 39 insertions(+), 17 deletions(-)
 create mode 100644 pez.png
 create mode 100644 ycomb.pez

diff --git a/bench.lua b/bench.lua
index 18e8116..b653cc9 100644
--- a/bench.lua
+++ b/bench.lua
@@ -1,4 +1,4 @@
-function fib(n)
+local function fib(n)
   if n < 2 then return n end
   return fib(n - 2) + fib(n - 1)
 end
diff --git a/pez.c b/pez.c
index 098b2ff..98f7d08 100644
--- a/pez.c
+++ b/pez.c
@@ -131,8 +131,10 @@ struct cmupval {
 
 typedef struct Comp {
     PezContext *cx;
-    int (*readcb)(void *);
+    PezReadFn *readcb;
     void *readud;
+    char rdbuf[1024];
+    uint rdbufi, rdbufsiz;
     uint line, col;
     int peekchr;
     bool have_peekchr;
@@ -2236,7 +2238,7 @@ initcore(PezContext *cx)
 /*******************/
 
 static void
-initcomp(Comp *cm, PezContext *cx, Proto *pr, int (*cb)(void *), void *ud)
+initcomp(Comp *cm, PezContext *cx, Proto *pr, PezReadFn cb, void *ud)
 {
     memset(cm, 0, sizeof *cm);
     cm->cx = cx;
@@ -2547,12 +2549,21 @@ endscope(Comp *cm)
 static int
 nextchr(Comp *cm)
 {
-    int c;
+    int c, n;
     if (cm->have_peekchr) {
         cm->have_peekchr = 0;
         return cm->peekchr;
     }
-    c = cm->readcb(cm->readud);
+    if (cm->rdbufsiz == 0) {
+        cm->rdbufi = 0;
+        if ((n = cm->readcb(cm->readud, cm->rdbuf, sizeof cm->rdbuf)) <= 0)
+            return EOF;
+        assert(n <= sizeof cm->rdbuf);
+        cm->rdbufsiz = n;
+    }
+    c = cm->rdbuf[cm->rdbufi++];
+    cm->rdbufi %= sizeof cm->rdbuf;
+    --cm->rdbufsiz;
     if (c == '\n') {
         ++cm->line;
         cm->col = 0;
@@ -3998,13 +4009,13 @@ block(Comp *cm, int endchr)
 /**************/
 
 bool
-pez_eval_cb(PezContext *cx, const char *fname, int (*cb)(void *), void *ud)
+pez_eval_cb(PezContext *cx, const char *fname, PezReadFn cb, void *ud)
 {
     Val *stktop = cx->stktop;
     Proto *pr;
     Fn *fn;
-    struct fenv fenv = {0};
     Comp cm;
+    struct fenv fenv = {0};
     int gccanrun = cx->gccanrun;
     cx->gccanrun = 0;
     if (!(pr = newproto(cx, fname, "<eval>", /* line */ 1))) {
@@ -4046,15 +4057,14 @@ Err:
 }
 
 static int
-str_read_cb(void *ud)
+str_read_cb(void *ud, char *dst, int n)
 {
+    int i;
     char **s = ud;
-    char c = **s;
-    if (c == 0) {
-        return EOF;
+    for (i = 0; **s && n > 0; ++i) {
+        *dst++ = *(*s)++;
     }
-    ++*s;
-    return c;
+    return i;
 }
 
 bool
@@ -4064,10 +4074,17 @@ pez_eval_str(PezContext *cx, const char *fname, const char *str)
     return pez_eval_cb(cx, fname, str_read_cb, &str);
 }
 
+static int
+file_read_cb(void *ud, char *dst, int n)
+{
+    FILE *fp = ud;
+    return fread(dst, 1, n, fp);
+}
+
 bool pez_eval_file(PezContext *cx, const char *fname, FILE *fp)
 {
     assert(fp);
-    return pez_eval_cb(cx, fname, (int(*)(void *))fgetc, fp);
+    return pez_eval_cb(cx, fname, file_read_cb, fp);
 }
 
 static void *
@@ -4327,7 +4344,7 @@ pez_checksig(PezContext *cx, int argc, const char *fn, const char *sig)
     for (; *sig; ++arg) {
         uint mask = 0;
         const char *this = sig;
-        int thisn;
+        int thisn = 0;
         int typ;
         typ = 1 << pez_typeof(cx, -argc + arg);
         do {
diff --git a/pez.h b/pez.h
index 081634b..2330f1b 100644
--- a/pez.h
+++ b/pez.h
@@ -33,6 +33,7 @@ typedef enum PezError {
 typedef struct PezContext PezContext;
 typedef void *PezAllocFn(void *userdata, void *ptr, size_t oldsize, size_t newsize);
 typedef bool PezCFn(PezContext *, int argc);
+typedef int PezReadFn(void *userdata, char *dst, int n);
 
 PezContext *pez_new(PezAllocFn *alloc, void *userdata, size_t stacksize);
 void pez_del(PezContext *);
@@ -49,7 +50,7 @@ void pez_debug(PezContext *, const char *opts);
 int pez_geterrno(PezContext *);
 const char *pez_geterr(PezContext *cx);
 
-bool pez_eval_cb(PezContext *, const char *fname, int (*cb)(void *), void *);
+bool pez_eval_cb(PezContext *, const char *fname, PezReadFn cb, void *);
 bool pez_eval_str(PezContext *, const char *fname, const char *);
 bool pez_eval_file(PezContext *, const char *path, FILE *);
 
diff --git a/pez.png b/pez.png
new file mode 100644
index 0000000..e415103
Binary files /dev/null and b/pez.png differ
diff --git a/test.pez b/test.pez
index 7f35b30..cd7d608 100644
--- a/test.pez
+++ b/test.pez
@@ -34,7 +34,6 @@ printf["%a == %a\n", m[3,7], 3^7]
     acc
 }
 
-
 printf["4+1+3: %a\n", add[4,1,3]]
 
 @gather: {[*]
diff --git a/ycomb.pez b/ycomb.pez
new file mode 100644
index 0000000..dff0f40
--- /dev/null
+++ b/ycomb.pez
@@ -0,0 +1,5 @@
+@Y: {[f] {[i] i[i]}[{[i] f[{[x] i[i][x]}]}]}
+
+@fact: {[n] Y[{[f] {[n] n == 0 ? 1 : n * f[n - 1]}}][n]}
+
+printf["%a\n", fact[5]]
-- 
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