From 7f8d0429d2f39b0dfb241ca63403df0452ddc385 Mon Sep 17 00:00:00 2001
From: tmeissner <programming@goodcleanfun.de>
Date: Fri, 10 May 2019 00:19:25 +0200
Subject: [PATCH] Add implementations for remaining functions

* Add list, eval & join functions
* Use new macro LASSERT for error checks
---
 chapter_10/lispy.c | 94 ++++++++++++++++++++++++++++++++++------------
 chapter_10/lispy.h |  8 ++++
 2 files changed, 78 insertions(+), 24 deletions(-)

diff --git a/chapter_10/lispy.c b/chapter_10/lispy.c
index 1246401..bafa75d 100644
--- a/chapter_10/lispy.c
+++ b/chapter_10/lispy.c
@@ -418,20 +418,14 @@ lval* builtin_op(lval* a, char* op) {
 lval* builtin_head(lval* a) {
 
     /* Check error conditions */
-    if (a->count != 1) {
-        lval_del(a);
-        return lval_err("Function 'head' passed too many arguments");
-    }
+    LASSERT(a, a->count == 1,
+            "Function 'head' passed too many arguments!");
 
-    if (a->cell[0]->type != LVAL_QEXPR) {
-        lval_del(a);
-        return lval_err("Function 'head' passed incorrect types!");
-    }
+    LASSERT(a, a->cell[0]->type == LVAL_QEXPR,
+        "Function 'head' passed incorrect type!");
 
-    if (a->cell[0]->count == 0) {
-        lval_del(a);
-        return lval_err("Function 'head' passed empty {}!");
-    }
+    LASSERT(a, a->cell[0]->count != 0,
+        "Function 'head' passed {}!");
 
     /* Otherwise take first argument */
     lval* v = lval_take(a, 0);
@@ -449,20 +443,14 @@ lval* builtin_head(lval* a) {
 lval* builtin_tail(lval* a) {
 
     /* Check error conditions */
-    if (a->count != 1) {
-        lval_del(a);
-        return lval_err("Function 'tail' passed too many arguments");
-    }
+    LASSERT(a, a->count == 1,
+            "Function 'tail' passed too many arguments!");
 
-    if (a->cell[0]->type != LVAL_QEXPR) {
-        lval_del(a);
-        return lval_err("Function 'tail' passed incorrect types!");
-    }
+    LASSERT(a, a->cell[0]->type == LVAL_QEXPR,
+        "Function 'tail' passed incorrect type!");
 
-    if (a->cell[0]->count == 0) {
-        lval_del(a);
-        return lval_err("Function 'tail' passed empty {}!");
-    }
+    LASSERT(a, a->cell[0]->count != 0,
+        "Function 'tail' passed {}!");
 
     /* Otherwise take first argument */
     lval* v = lval_take(a, 0);
@@ -475,6 +463,64 @@ lval* builtin_tail(lval* a) {
 }
 
 
+lval* builtin_list(lval* a) {
+
+    a->type = LVAL_QEXPR;
+    return a;
+
+}
+
+
+lval* builtin_eval(lval* a) {
+
+    /* Check error conditions */
+    LASSERT(a, a->count == 1,
+            "Function 'eval' passed too many arguments!");
+
+    LASSERT(a, a->cell[0]->type == LVAL_QEXPR,
+        "Function 'eval' passed incorrect type!");
+
+    lval* x = lval_take(a, 0);
+    x->type = LVAL_SEXPR;
+    return lval_eval(x);
+
+}
+
+
+lval* builtin_join(lval* a) {
+
+    /* Check error conditions */
+    for (size_t i = 0; i < a->count; i++) {
+        LASSERT(a, a->cell[i]->type == LVAL_QEXPR,
+        "Function 'join' passed incorrect type!");
+    }
+
+    lval* x = lval_pop(a, 0);
+
+    while (a->count) {
+        x = lval_join(x, lval_pop(a, 0));
+    }
+
+    lval_del(a);
+    return x;
+
+}
+
+
+lval* lval_join(lval* x, lval* y) {
+
+    /* For each cell in y add it to x */
+    while (y->count) {
+        x = lval_add(x, lval_pop(y, 0));
+    }
+
+    /* Delete the empty y and return x */
+    lval_del(y);
+    return x;
+
+}
+
+
 long min(long x, long y) {
     if (x <= y) {
         return x;
diff --git a/chapter_10/lispy.h b/chapter_10/lispy.h
index bba67f5..3074aba 100644
--- a/chapter_10/lispy.h
+++ b/chapter_10/lispy.h
@@ -1,3 +1,7 @@
+#define LASSERT(args, cond, err)  \
+    if (!(cond)) { lval_del(args); return lval_err(err); }
+
+
 static char* lispy_version = "Lispy version 0.0.0.0.6";
 
 
@@ -69,3 +73,7 @@ long max(long x, long y);
 lval* builtin_op(lval* a, char* op);
 lval* builtin_head(lval* a);
 lval* builtin_tail(lval* a);
+lval* builtin_list(lval* a);
+lval* builtin_eval(lval* a);
+lval* builtin_join(lval* a);
+lval* lval_join(lval* x, lval* y);