Merge pull request #182 from mdaines/sqrt-builtin

Add builtin for calculating square root

3 files changed, 29 insertions, 0 deletions

diff --git a/builtin.c b/builtin.c
index a61e8204..721cd3fc 100644
--- a/builtin.c
+++ b/builtin.c
@@ -59,6 +59,15 @@ static jv f_floor(jv input) {
   return ret;
 }
 
+static jv f_sqrt(jv input) {
+  if (jv_get_kind(input) != JV_KIND_NUMBER) {
+    return type_error(input, "has no square root");
+  }
+  jv ret = jv_number(sqrt(jv_number_value(input)));
+  jv_free(input);
+  return ret;
+}
+
 static jv f_negate(jv input) {
   if (jv_get_kind(input) != JV_KIND_NUMBER) {
     return type_error(input, "cannot be negated");
@@ -474,6 +483,7 @@ static jv f_error(jv input, jv msg) {
 
 static const struct cfunction function_list[] = {
   {(cfunction_ptr)f_floor, "_floor", 1},
+  {(cfunction_ptr)f_sqrt, "_sqrt", 1},
   {(cfunction_ptr)f_plus, "_plus", 3},
   {(cfunction_ptr)f_negate, "_negate", 1},
   {(cfunction_ptr)f_minus, "_minus", 3},
@@ -559,6 +569,7 @@ static const char* const jq_builtins[] = {
   "def max_by(f): _max_by_impl(map([f]));",
   "def min_by(f): _min_by_impl(map([f]));",
   "def floor: _floor;",
+  "def sqrt: _sqrt;",
   "def add: reduce .[] as $x (null; . + $x);",
   "def del(f): delpaths([path(f)]);",
   "def _assign(paths; value): value as $v | reduce path(paths) as $p (.; setpath($p; $v));",
diff --git a/docs/content/3.manual/manual.yml b/docs/content/3.manual/manual.yml
index 26779549..6fb83940 100644
--- a/docs/content/3.manual/manual.yml
+++ b/docs/content/3.manual/manual.yml
@@ -633,6 +633,16 @@ sections:
             input: '3.14159'
             output: ['3']
             
+      - title: `sqrt`
+        body: |
+
+          The `sqrt` function returns the square root of its numeric input.
+
+        examples:
+          - program: 'sqrt'
+            input: '9'
+            output: ['3']
+            
       - title: `tonumber`
         body: |
 
diff --git a/tests/all.test b/tests/all.test
index af6f8a1c..c16b7eba 100644
--- a/tests/all.test
+++ b/tests/all.test
@@ -366,6 +366,14 @@ null
 [-1.1,1.1,1.9]
 [-2, 1, 1]
 
+[.[]|sqrt]
+[4,9]
+[2,3]
+
+(add / length) as $m | map((. - $m) as $d | $d * $d) | add / length | sqrt
+[2,4,4,4,5,5,7,9]
+2
+
 def f(x): x | x; f([.], . + [42])
 [1,2,3]
 [[[1,2,3]]]