min, max

6 files changed, 90 insertions, 1 deletions

diff --git a/src/builtins.c b/src/builtins.c
index 198f80d..fbf5855 100644
--- a/src/builtins.c
+++ b/src/builtins.c
@@ -2,6 +2,88 @@
 #include "interp.h"
 #include "sexp.h"
 #include <algds/str.h>
+#include <stdint.h>
+#include <float.h>
+
+SExpRef builtin_min(Interp *interp, SExpRef args) {
+    if (LENGTH(args) < 1) return new_error(interp, "min: wrong arg number.\n");
+    bool hasReal = false;
+    FOREACH(iter, args) {
+        SExpRef x = CAR(iter);
+        if (VALTYPE(x) == kRealSExp) hasReal = true;
+        if (VALTYPE(x) != kRealSExp && VALTYPE(x) != kIntegerSExp) {
+            return new_error(interp, "min: wrong type.\n");
+        }
+    }
+    if (hasReal) {
+        double min = DBL_MAX;
+        FOREACH(iter, args) {
+            SExpRef x = CAR(iter);
+            if (VALTYPE(x) == kIntegerSExp) {
+                if (REF(x)->integer < min) {
+                    min = REF(x)->integer;
+                }
+            }
+            if (VALTYPE(x) == kRealSExp) {
+                if (REF(x)->real < min) {
+                    min = REF(x)->real;
+                }
+            }
+        }
+        return new_integer(interp, min);
+    } else {
+        int64_t min = INT64_MAX;
+        FOREACH(iter, args) {
+            SExpRef x = CAR(iter);
+            if (VALTYPE(x) == kIntegerSExp) {
+                if (REF(x)->integer < min) {
+                    min = REF(x)->integer;
+                }
+            }
+        }
+        return new_integer(interp, min);
+    }
+}
+
+SExpRef builtin_max(Interp *interp, SExpRef args) {
+    if (LENGTH(args) < 1) return new_error(interp, "min: wrong arg number.\n");
+    bool hasReal = false;
+    FOREACH(iter, args) {
+        SExpRef x = CAR(iter);
+        if (VALTYPE(x) == kRealSExp) hasReal = true;
+        if (VALTYPE(x) != kRealSExp && VALTYPE(x) != kIntegerSExp) {
+            return new_error(interp, "min: wrong type.\n");
+        }
+    }
+    if (hasReal) {
+        double max = -DBL_MAX;
+        FOREACH(iter, args) {
+            SExpRef x = CAR(iter);
+            if (VALTYPE(x) == kIntegerSExp) {
+                if (REF(x)->integer > max) {
+                    max = REF(x)->integer;
+                }
+            }
+            if (VALTYPE(x) == kRealSExp) {
+                if (REF(x)->real > max) {
+                    max = REF(x)->real;
+                }
+            }
+        }
+        return new_real(interp, max);
+    } else {
+        int64_t max = INT64_MIN;
+        FOREACH(iter, args) {
+            SExpRef x = CAR(iter);
+            if (VALTYPE(x) == kIntegerSExp) {
+                if (REF(x)->integer > max) {
+                    max = REF(x)->integer;
+                }
+            }
+        }
+        return new_integer(interp, max);
+    }
+}
 
 static bool equal_impl(Interp *interp, SExpRef x, SExpRef y) {
     if (VALTYPE(x) != VALTYPE(y)) return false;
diff --git a/src/builtins.h b/src/builtins.h
index b5a0979..abcd7a0 100644
--- a/src/builtins.h
+++ b/src/builtins.h
@@ -3,6 +3,8 @@
 
 #include "interp.h"
 
+SExpRef builtin_min(Interp *interp, SExpRef sexp);
+SExpRef builtin_max(Interp *interp, SExpRef sexp);
 SExpRef builtin_equal(Interp *interp, SExpRef sexp);
 SExpRef builtin_eq(Interp *interp, SExpRef sexp);
 SExpRef builtin_format(Interp *interp, SExpRef sexp);
diff --git a/src/interp.c b/src/interp.c
index d7e06ed..8813d37 100644
--- a/src/interp.c
+++ b/src/interp.c
@@ -86,6 +86,8 @@ void Interp_init(Interp *self) {
     Interp_add_primitive(self, "assert-error", primitive_assert_error);
     Interp_add_primitive(self, "load", primitive_load);
 
+    Interp_add_userfunc(self, "min", builtin_min);
+    Interp_add_userfunc(self, "max", builtin_max);
     Interp_add_userfunc(self, "eq", builtin_eq);
     Interp_add_userfunc(self, "equal", builtin_equal);
     Interp_add_userfunc(self, "format", builtin_format);
diff --git a/src/interp.h b/src/interp.h
index 74bb0dd..36fd1e0 100644
--- a/src/interp.h
+++ b/src/interp.h
@@ -53,6 +53,7 @@ SExpRef Interp_load_file(Interp *interp, const char *filename);
 #define EVAL(_x) (lisp_eval(interp, (_x), false))
 #define EVALTAIL(_x) (lisp_eval(interp, (_x), true))
 #define TRUEP(_x) (lisp_truep(interp, (_x)))
+#define FOREACH(_x, _lst) for (SExpRef _x = _lst; !NILP(_x); _x = CDR(_x))
 // control flow
 #define CTL_FL(_x) \
     (REF((_x))->type == kErrSignal \
diff --git a/src/prelude.c b/src/prelude.c
index 1389f28..3d1a971 100644
--- a/src/prelude.c
+++ b/src/prelude.c
@@ -1,6 +1,6 @@
 
 #include "prelude.h"
 
-const char *bamboo_lisp_prelude = "(defvar nil \'())\n\n(defvar pi 3.1415926)\n\n(defmacro incq (i)\n  `(setq ,i (+ ,i 1)))\n\n(defmacro decq (i)\n  `(setq ,i (- ,i 1)))\n\n(defun zerop (x) (= x 0))\n\n(defmacro when (pred . body)\n  `(if ,pred\n     (progn ,@body)\n     nil))\n\n(defmacro unless (pred . body)\n  `(if ,pred\n     nil\n     (progn ,@body)))\n";
+const char *bamboo_lisp_prelude = "(defvar nil \'())\n\n(defvar pi 3.1415926)\n\n(defmacro incq (i)\n  `(setq ,i (+ ,i 1)))\n\n(defmacro decq (i)\n  `(setq ,i (- ,i 1)))\n\n(defun zerop (x) (= x 0))\n(defun plusp (x) (> x 0))\n(defun minusp (x) (< x 0))\n\n(defmacro when (pred . body)\n  `(if ,pred\n     (progn ,@body)\n     nil))\n\n(defmacro unless (pred . body)\n  `(if ,pred\n     nil\n     (progn ,@body)))\n";
 
 
diff --git a/src/prelude.lisp b/src/prelude.lisp
index 7b49977..df85a9b 100644
--- a/src/prelude.lisp
+++ b/src/prelude.lisp
@@ -9,6 +9,8 @@
   `(setq ,i (- ,i 1)))
 
 (defun zerop (x) (= x 0))
+(defun plusp (x) (> x 0))
+(defun minusp (x) (< x 0))
 
 (defmacro when (pred . body)
   `(if ,pred