Converts gas, mat and reagent strings to defines

code/game/objects/structures/bonfire.dm

@@ -150,7 +150,7 @@
 
 /obj/structure/bonfire/proc/check_oxygen()
 	var/datum/gas_mixture/G = loc.return_air()
-	if(G.gas["oxygen"] < 1)
+	if(G.gas[GAS_O2] < 1)
 		return FALSE
 	return TRUE
 
@@ -345,7 +345,7 @@
 
 /obj/structure/fireplace/proc/check_oxygen()
 	var/datum/gas_mixture/G = loc.return_air()
-	if(G.gas["oxygen"] < 1)
+	if(G.gas[GAS_O2] < 1)
 		return FALSE
 	return TRUE
 

code/game/objects/structures/crates_lockers/closets/coffin.dm

@@ -149,7 +149,7 @@
 	return PROJECTILE_CONTINUE	// It's a hole in the ground, doesn't usually stop or even care about bullets
 
 /obj/structure/closet/grave/return_air_for_internal_lifeform(var/mob/living/L)
-	var/gasid = "carbon_dioxide"
+	var/gasid = GAS_CO2
 	if(ishuman(L))
 		var/mob/living/carbon/human/H = L
 		if(H.species && H.species.exhale_type)

code/game/objects/structures/door_assembly.dm

@@ -267,7 +267,7 @@
 		var/material_name = S.get_material_name()
 		if (S)
 			if (S.get_amount() >= 1)
-				if(material_name == "rglass")
+				if(material_name == MAT_RGLASS)
 					playsound(src, 'sound/items/Crowbar.ogg', 100, 1)
 					user.visible_message("[user] adds [S.name] to the airlock assembly.", "You start to install [S.name] into the airlock assembly.")
 					if(do_after(user, 4 SECONDS, src, exclusive = TASK_ALL_EXCLUSIVE) && !glass)
@@ -276,7 +276,7 @@
 							glass = 1
 				else if(material_name)
 					// Ugly hack, will suffice for now. Need to fix it upstream as well, may rewrite mineral walls. ~Z
-					if(!(material_name in list("gold", "silver", "diamond", "uranium", "phoron", "sandstone")))
+					if(!(material_name in list(MAT_GOLD, MAT_SILVER, MAT_DIAMOND, MAT_URANIUM, MAT_PHORON, MAT_SANDSTONE)))
 						to_chat(user, "You cannot make an airlock out of that material.")
 						return
 					if(S.get_amount() >= 2)

code/game/objects/structures/droppod.dm

@@ -141,5 +141,5 @@
 /datum/gas_mixture/pod_air/New()
     . = ..()
     gas = list(
-        "oxygen" = 21,
-        "nitrogen" = 79)
+        GAS_O2 = 21,
+        GAS_N2 = 79)

code/game/objects/structures/simple_doors.dm

@@ -242,25 +242,25 @@
 	SSradiation.radiate(src, round(material.radioactivity/3))
 
 /obj/structure/simple_door/iron/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "iron")
+	..(mapload, material_name || MAT_IRON)
 
 /obj/structure/simple_door/silver/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "silver")
+	..(mapload, material_name || MAT_SILVER)
 
 /obj/structure/simple_door/gold/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "gold")
+	..(mapload, material_name || MAT_GOLD)
 
 /obj/structure/simple_door/uranium/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "uranium")
+	..(mapload, material_name || MAT_URANIUM)
 
 /obj/structure/simple_door/sandstone/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "sandstone")
+	..(mapload, material_name || MAT_SANDSTONE)
 
 /obj/structure/simple_door/phoron/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "phoron")
+	..(mapload, material_name || MAT_PHORON)
 
 /obj/structure/simple_door/diamond/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "diamond")
+	..(mapload, material_name || MAT_DIAMOND)
 
 /obj/structure/simple_door/wood/Initialize(mapload,var/material_name)
 	..(mapload, material_name || MAT_WOOD)
@@ -273,10 +273,10 @@
 	..(mapload, material_name || MAT_SIFWOOD)
 
 /obj/structure/simple_door/resin/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "resin")
+	..(mapload, material_name || MAT_RESIN)
 
 /obj/structure/simple_door/cult/Initialize(mapload,var/material_name)
-	..(mapload, material_name || "cult")
+	..(mapload, material_name || MAT_CULT)
 
 /obj/structure/simple_door/cult/TryToSwitchState(atom/user)
 	if(isliving(user))

code/game/objects/structures/transit_tubes.dm

@@ -81,7 +81,7 @@
 /obj/structure/transit_tube_pod/New(loc)
 	..(loc)
 
-	air_contents.adjust_multi("oxygen", MOLES_O2STANDARD * 2, "nitrogen", MOLES_N2STANDARD)
+	air_contents.adjust_multi(GAS_O2, MOLES_O2STANDARD * 2, GAS_N2, MOLES_N2STANDARD)
 	air_contents.temperature = T20C
 
 	// Give auto tubes time to align before trying to start moving