Add math function that return the enchantment value

doc/JSON/NPCs.md

@@ -1404,6 +1404,7 @@ _some functions support array arguments or kwargs, denoted with square brackets
 | calories()    |  ✅   |   ✅  | u, n  | Return amount of calories character has. If used on item, return amount of calories this item gives when consumed (not affected by enchantments or mutations).  Optional kwargs:<br/>`format`: `s`/`v` - return the value in specific format.  Can be `percent` (return percent to the healthy amount of calories, `100` being the target, bmi 25, or 110000 kcal) or `raw`.  If now used, `raw` is used by default.<br/>`dont_affect_weariness`: `true`/`false` (default false) When assigning value, whether the gained/spent calories should be tracked by weariness.<br/><br/>Example:<br/>`"condition": { "math": [ "u_calories() < 0" ] }`<br/>`"condition": { "math": [ "u_calories('format': 'percent') > 0" ] }`<br/>`"condition": { "math": [ "u_calories() = 110000" ] }`|
 | get_calories_daily()  |  ✅   |   ❌  | g  | Return amount of calories character consumed before, up to 30 days, in kcal. Calorie diary is something only character has, so it can't be used with NPCs. Optional kwargs:<br/>`day`: `d/v` - picks the date the value would be pulled from, from 0 to 30. Default 0, meaning amount of calories you consumed today.<br/>`type`: `s/v` - picks the data that would be pulled. Possible values are: `spent` - how much calories character spent in different activities throughout the day; `gained` - how much calories character ate that day; `ingested` - how much calories character processed that day; `total` - `gained` minus `spent`. Default is `total`;<br/><br/>Example:<br/>`"condition": { "math": [ "get_calories_daily() > 1000" ] }`<br/> `{ "math": [ "foo = get_calories_daily('type':'gained', 'day':'1')" ] }`|
 | quality( `s` / `v` )  |  ✅   |   ❌  | u, n | Return the level of a specified item tool quality. Only usable on item talkers.<br/>Argument is the quality ID. Returns the lowest integer value if the item lacks the specified quality.<br/>Optional kwargs:<br/>`strict`: `true` / `false` (default false) When true the item must be empty to have the boiling quality.<br/><br/>Example<br/>`"condition: { "math": [ " u_quality('HACK') > 0 " ] }`<br/>`{ "math": [ "_cut_quality = u_quality('CUT') " ] }`<br/>`condition: { "math": [ " u_quality('BOIL', 'strict': true ) > 0" ] }`
+| enchantment(`s`/`v`)    |  ✅   |   ❌  | u, n  | Return the result of the enchantment that you have, both `add` and `multiply` fields.<br/>Argument is enchantment id.<br/><br/>Example:<br/>`{ "math": [ "_x = u_enchantment('ARTIFACT_RESONANCE')" ] }`|
 
 #### List of Character and item aspects
 These can be read or written to with `val()`.

src/math_parser_diag.cpp

@@ -1287,6 +1287,18 @@ double proficiency_eval( const_dialogue const &d, char scope, std::vector<diag_v
     }
 }
 
+double enchantment_eval( const_dialogue const &d, char scope, std::vector<diag_value> const &params,
+                         diag_kwargs const &/* kwargs */ )
+{
+    const std::optional<enchant_vals::mod> mod_val = io::string_to_enum_optional<enchant_vals::mod>
+            ( params[0].str( d ) );
+    if( mod_val.has_value() ) {
+        return d.const_actor( is_beta( scope ) )->enchantment_value( mod_val.value() );
+    } else {
+        throw math::runtime_error( "Incorrect enchantment value id" );
+    }
+}
+
 void proficiency_ass( double val, dialogue &d, char scope, std::vector<diag_value> const &params,
                       diag_kwargs const &kwargs )
 {
@@ -1698,6 +1710,7 @@ std::map<std::string_view, dialogue_func> const dialogue_funcs{
     { "moon_phase", { "g", 0, moon_phase_eval } },
     { "num_input", { "g", 2, num_input_eval } },
     { "pain", { "un", 0, pain_eval, pain_ass, { "type" } } },
+    { "enchantment", { "un", 1, enchantment_eval } },
     { "school_level", { "un", 1, school_level_eval } },
     { "school_level_adjustment", { "un", 1, school_level_adjustment_eval, school_level_adjustment_ass } },
     { "spellcasting_adjustment", { "u", 1, {}, spellcasting_adjustment_ass, { "mod", "school", "spell", "flag_whitelist", "flag_blacklist" } } },

src/talker.h

@@ -261,6 +261,9 @@ class const_talker
         virtual bool knows_spell( const spell_id & ) const {
             return false;
         }
+        virtual double enchantment_value( const enchant_vals::mod ) const {
+            return 0.0;
+        }
         virtual bool knows_proficiency( const proficiency_id & ) const {
             return false;
         }

src/talker_character.cpp

@@ -1,4 +1,4 @@
 #include <algorithm>
 #include <bitset>
 #include <cmath>
 #include <cstddef>
@@ -394,6 +394,14 @@
     return me_chr_const->has_max_power();
 }
 
+double talker_character_const::enchantment_value( const enchant_vals::mod mod ) const
+{
+    double value;
+    value = me_chr_const->enchantment_cache->get_value_add( mod );
+    value *= 1.0 + me_chr_const->enchantment_cache->get_value_multiply( mod );
+    return value;
+}
+
 void talker_character::set_power_cur( units::energy value )
 {
     me_chr->set_power_level( value );

src/talker_character.h

@@ -89,6 +89,7 @@
         bool crossed_threshold() const override;
         int num_bionics() const override;
         bool has_max_power() const override;
+        double enchantment_value( const enchant_vals::mod mod ) const override;
         bool has_bionic( const bionic_id &bionics_id ) const override;
         bool knows_spell( const spell_id &sp ) const override;
         int get_skill_level( const skill_id & ) const override;