support single and double quotes in key value pairs also

escape characters not supported in double quotes

examples/grid/material.yaml

@@ -6,29 +6,29 @@ homogenization:
 
 phase:
   Aluminum:
-    lattice: "cF"
+    "lattice": 'cF'
     mechanical:
       output: [F, P, F_e, F_p, L_p, O]
       elastic: {type: "Hooke", C_11: 106.75e+9, C_12: 60.41e+9, C_44: 28.34e+9}
       plastic:
-        type: phenopowerlaw
-        N_sl: [12]
+        'type': "phenopowerlaw"
+        "N_sl": [12]
         a_sl: 2.25
         atol_xi: 1.0
         dot_gamma_0_sl: 0.001
         h_0_sl-sl: 75.e+6
         h_sl-sl: [1, 1, 1.4, 1.4, 1.4, 1.4, 1.4]
         n_sl: 20
-        output: ["xi_sl"]
+        'output': ['xi_sl']
         xi_0_sl: [31.e+6]
         xi_inf_sl: [63.e+6]
 
 material:
   - homogenization: SX
     constituents:
-      - phase: Aluminum
-        v: 1.0
-        O: [1.0, 0.0, 0.0, 0.0]
+      - 'phase': "Aluminum"
+        'v': 1.0
+        "O": [1.0, 0.0, 0.0, 0.0]
   - homogenization: SX
     constituents:
       - phase: Aluminum

src/YAML_parse.f90

@@ -71,8 +71,8 @@ recursive function parse_flow(YAML_flow) result(node)
       s = e
       d = s + scan(flow_string(s+1:),':')
       e = d + find_end(flow_string(d+1:),'}')
-
       key = trim(adjustl(flow_string(s+1:d-1)))
+      if (key(1:1) == '"' .or. key(1:1) == "'" ) key = key(2:len(key)-1)
       myVal => parse_flow(flow_string(d+1:e-1))                                                     ! parse items (recursively)
 
       select type (node)
@@ -97,7 +97,7 @@ recursive function parse_flow(YAML_flow) result(node)
     allocate(tScalar::node)
       select type (node)
         class is (tScalar)
-          if(flow_string(1:1) == '"') then
+          if (flow_string(1:1) == '"' .or. flow_string(1:1) == "'") then
             node = trim(adjustl(flow_string(2:len(flow_string)-1)))
           else
             node = trim(adjustl(flow_string))
@@ -125,7 +125,7 @@ integer function find_end(str,e_char)
   N_cu = 0
   i = 1
   do while(i<=len_trim(str))
-    if (str(i:i) == '"') i = i + scan(str(i+1:),'"')
+    if (str(i:i) == '"' .or. str(i:i) == "'") i = i + scan(str(i+1:),str(i:i))
     if (N_sq==0 .and. N_cu==0 .and. scan(str(i:i),e_char//',') == 1) exit
     N_sq = N_sq + merge(1,0,str(i:i) == '[')
     N_cu = N_cu + merge(1,0,str(i:i) == '{')