diff --git a/wdl2cwl/main.py b/wdl2cwl/main.py
index a56b5300..083cc539 100644
--- a/wdl2cwl/main.py
+++ b/wdl2cwl/main.py
@@ -727,7 +727,11 @@ def get_workflow_outputs(
             with WDLSourceLine(item.info, ConversionException):
                 output_name = item.name
                 item_expr = item.info.expr
-                output_source = item_expr.expr.name[::-1].replace(".", "/", 1)[::-1]
+                if isinstance(item_expr, WDL.Expr.Get):
+                    output_source = item_expr.expr.name[::-1].replace(".", "/", 1)[::-1]
+                else:
+                    output_source = f"$({self.get_expr(item_expr)})"
+
                 # replace just the last occurrence of a period with a slash
                 # by first reversing the string and the replace the first occurrence
                 # then reversing the result
@@ -1024,16 +1028,20 @@ def get_expr_get(self, wdl_get_expr: WDL.Expr.Get) -> str:
 
     def get_expr_ident(self, wdl_ident_expr: WDL.Expr.Ident) -> str:
         """Translate WDL Ident Expressions."""
-        id_name = wdl_ident_expr.name
+        id_name: str = wdl_ident_expr.name
         referee = wdl_ident_expr.referee
         optional = wdl_ident_expr.type.optional
         if referee:
             with WDLSourceLine(referee, ConversionException):
                 if isinstance(referee, WDL.Tree.Call):
                     return id_name
-                if referee.expr and (
-                    wdl_ident_expr.name in self.optional_cwl_null
-                    or wdl_ident_expr.name not in self.non_static_values
+                if (
+                    hasattr(referee, "expr")
+                    and referee.expr is not None
+                    and (
+                        wdl_ident_expr.name in self.optional_cwl_null
+                        or wdl_ident_expr.name not in self.non_static_values
+                    )
                 ):
                     return self.get_expr(referee.expr)
         ident_name = get_input(id_name)
diff --git a/wdl2cwl/tests/cwl_files/blast.cwl b/wdl2cwl/tests/cwl_files/blast.cwl
new file mode 100644
index 00000000..fb588a4f
--- /dev/null
+++ b/wdl2cwl/tests/cwl_files/blast.cwl
@@ -0,0 +1,335 @@
+cwlVersion: v1.2
+$graph:
+- class: Workflow
+  id: main
+  inputs:
+    - id: blast_docker_override
+      type:
+        - string
+        - 'null'
+    - id: blast_docker
+      type: string
+      # TODO: how to translate the original?
+      #       String blast_docker = select_first([blast_docker_override,"swr.cn-south-1.myhuaweicloud.com/cngbdb/blast:1.2"])
+    - id: queryfa
+      type: File
+    - id: fname
+      type: string
+      default: '/sfs/blastdb/2019_ncov/nucl/v6/ncov'
+    - id: method
+      type: string
+      default: 'blastn'
+    - id: outfmt
+      type: int
+      default: 7
+    - id: evalue
+      type: float
+      default: 10
+    # TODO: how to translate the original?
+    #       String Outfile = basename(queryfa)+'.blast_result.txt'
+    - id: Outfile
+      type: string
+    # runblastn task inputs, to be linked from workflow -> tool
+    - id: runblastn.docker
+      type: string
+    - id: runblastn.Queryfa
+      type: File
+    - id: runblastn.Fname
+      type: string
+    - id: runblastn.max_target_seqs
+      default: 100
+      type: int
+    - id: runblastn.word_size
+      default: 28
+      type: int
+    - id: runblastn.reward
+      default: 1
+      type: int
+    - id: runblastn.penalty
+      default: -2
+      type: int
+    - id: runblastn.strand
+      default: both
+      type: string
+    - id: runblastn.gapopen
+      default: 0
+      type: int
+    - id: runblastn.gapextend
+      default: 0
+      type: int
+    - id: runblastn.dust
+      default: "'20 64 1'"
+      type: string
+    - id: runblastn.max_hsps
+      type:
+        - int
+        - 'null'
+    - id: runblastn.tasks
+      default: megablast
+      type: string
+    - id: runblastn.taxids
+      type:
+        - string
+        - 'null'
+    - id: runblastn.negative_taxids
+      type:
+        - string
+        - 'null'
+    - id: runblastn.lcase_masking
+      default: false
+      type: boolean
+    # runblastp task inputs, to be linked from workflow -> tool
+    - id: runblastp.docker
+      type: string
+    - id: runblastp.Queryfa
+      type: File
+    - id: runblastp.Fname
+      type: string
+    - id: runblastp.max_target_seqs
+      default: 100
+      type: int
+    - id: runblastp.word_size
+      default: 6
+      type: int
+    - id: runblastp.seg
+      default: no
+      type: string
+    - id: runblastp.comp_based_stats
+      default: '2'
+      type: string
+    - id: runblastp.matrix
+      default: BLOSUM62
+      type: string
+    - id: runblastp.gapopen
+      default: 11
+      type: int
+    - id: runblastp.gapextend
+      default: 1
+      type: int
+    - id: runblastp.max_hsps
+      type:
+        - int
+        - 'null'
+    - id: runblastp.taxids
+      type:
+        - string
+        - 'null'
+    - id: runblastp.negative_taxids
+      type:
+        - string
+        - 'null'
+    - id: runblastp.lcase_masking
+      default: false
+      type: boolean
+  steps:
+    - id: runblastp
+      in:
+        Fname: fname
+        Queryfa: queryfa
+        docker: blast_docker
+        outfmt: outfmt
+        Outfile: Outfile
+        threads: threads
+      run: runblastp
+      when: $(inputs.method == 'blastp')
+      out: [out]
+    - id: runblastn
+      in:
+        Fname: fname
+        Queryfa: queryfa
+        docker: blast_docker
+        outfmt: outfmt
+        evalue: evalue
+        Outfile: Outfile
+        threads: threads
+      run: runblastn
+      when: $(inputs.method == 'blastn')
+      out: [out]
+  outputs:
+    - id: fina_output
+      type: File
+      outputSource:
+        - runblastp/out
+        - runblastn/out
+      pickValue: first_non_null
+
+- class: CommandLineTool
+  id: runblastn
+  requirements:
+    - class: InitialWorkDirRequirement
+      listing:
+        - entryname: script.bash
+          entry: |4
+              set -e
+              blastn -db "$(inputs.Fname)" \
+              -show_gis \
+              -query $(inputs.QueryFa) \
+              -outfmt $(inputs.outfmt) \
+              -out     $(inputs.Outfile) \
+              -max_target_seqs $(inputs.max_target_seqs) \
+              -evalue $(inputs.evalue) \
+              -word_size $(inputs.word_size) \
+              -penalty $(inputs.penalty) \
+              -reward  $(inputs.reward) \
+              -dust $(inputs.dust) \
+              -gapopen $(inputs.gapopen) \
+              -gapextend $(inputs.gapextend) \
+              -task $(inputs.tasks) \
+              -strand  $(inputs.strand) \
+              -num_threads $(inputs.threads) \
+              $(true='-lcase_masking' false='' inputs.lcase_masking) $("-max_hsps "+ inputs.max_hsps) $("-taxids " +inputs.taxids) $("-negative_taxids " +inputs.negative_taxids)\
+  hints:
+    - class: DockerRequirement
+    - class: ResourceRequirement
+      coresMin: 8
+      ramMin: 16384
+  inputs:
+    - id: docker
+      type: string
+    - id: Queryfa
+      type: File
+    - id: Fname
+      type: string
+    - id: Outfile
+      type: string
+    - id: threads
+      type: int
+    - id: outfmt
+      type: int
+    - id: max_target_seqs
+      default: 100
+      type: int
+    - id: word_size
+      default: 28
+      type: int
+    - id: reward
+      default: 1
+      type: int
+    - id: penalty
+      default: -2
+      type: int
+    - id: strand
+      default: both
+      type: string
+    - id: gapopen
+      default: 0
+      type: int
+    - id: gapextend
+      default: 0
+      type: int
+    - id: dust
+      default: "'20 64 1'"
+      type: string
+    - id: max_hsps
+      type:
+        - int
+        - 'null'
+    - id: tasks
+      default: megablast
+      type: string
+    - id: taxids
+      type:
+        - string
+        - 'null'
+    - id: negative_taxids
+      type:
+        - string
+        - 'null'
+    - id: lcase_masking
+      default: false
+      type: boolean
+  baseCommand:
+    - bash
+    - script.bash
+  outputs:
+    - id: out
+      type: File
+      outputBinding:
+        glob: $(inputs.Outfile)
+
+- class: CommandLineTool
+  id: runblastp
+  requirements:
+    - class: InitialWorkDirRequirement
+      listing:
+        - entryname: script.bash
+          entry: |4
+              set -e
+              blastp -db "$(inputs.Fname)" \
+              -query $(inputs.Queryfa) \
+              -outfmt $(inputs.outfmt) \
+              -out     $(inputs.Outfile) \
+              -max_target_seqs $(inputs.max_target_seqs) \
+              -comp_based_stats $(inputs.comp_based_stats) \
+              -evalue $(inputs.evalue) \
+              -word_size $(inputs.word_size) \
+              -matrix   $(inputs.matrix) \
+              -seg     $(inputs.seg) \
+              -gapopen $(inputs.gapopen) \
+              -gapextend $(inputs.gapextend) \
+              -num_threads $(inputs.threads) \
+              $(true='-lcase_masking' false='' inputs.lcase_masking) $("-max_hsps "+inputs.max_hsps) $("-taxids " +inputs.taxids) $("-negative_taxids " +inputs.negative_taxids) \
+  hints:
+    - class: DockerRequirement
+    - class: ResourceRequirement
+      coresMin: 8
+      ramMin: 16384
+  inputs:
+    - id: docker
+      type: string
+    - id: Queryfa
+      type: File
+    - id: Fname
+      type: string
+    - id: outfmt
+      type: string
+    - id: Outfile
+      type: string
+    - id: evalue
+      type: float
+    - id: threads
+      type: int
+    - id: max_target_seqs
+      default: 100
+      type: int
+    - id: word_size
+      default: 6
+      type: int
+    - id: seg
+      default: no
+      type: string
+    - id: comp_based_stats
+      default: '2'
+      type: string
+    - id: matrix
+      default: BLOSUM62
+      type: string
+    - id: gapopen
+      default: 11
+      type: int
+    - id: gapextend
+      default: 1
+      type: int
+    - id: max_hsps
+      type:
+        - int
+        - 'null'
+    - id: taxids
+      type:
+        - string
+        - 'null'
+    - id: negative_taxids
+      type:
+        - string
+        - 'null'
+    - id: lcase_masking
+      default: false
+      type: boolean
+  baseCommand:
+    - bash
+    - script.bash
+  outputs:
+    - id: out
+      type: File
+      outputBinding:
+        glob: $(inputs.Outfile)
diff --git a/wdl2cwl/tests/test_cwl.py b/wdl2cwl/tests/test_cwl.py
index b2bd91a1..b1407df4 100644
--- a/wdl2cwl/tests/test_cwl.py
+++ b/wdl2cwl/tests/test_cwl.py
@@ -69,6 +69,7 @@ def test_meta(caplog: pytest.LogCaptureFixture) -> None:
         ("vt.wdl"),
         ("whatshap.wdl"),
         ("workflow_inputs.wdl"),
+        ("blast.wdl"),
     ],
 )
 def test_wdls(description_name: str) -> None:
diff --git a/wdl2cwl/tests/wdl_files/blast.wdl b/wdl2cwl/tests/wdl_files/blast.wdl
new file mode 100644
index 00000000..450c1661
--- /dev/null
+++ b/wdl2cwl/tests/wdl_files/blast.wdl
@@ -0,0 +1,325 @@
+version 1.0
+
+workflow blast {
+  input {
+    String? blast_docker_override
+    String  blast_docker= select_first([blast_docker_override,"swr.cn-south-1.myhuaweicloud.com/cngbdb/blast:1.2"])
+    File    queryfa
+    String  fname       = '/sfs/blastdb/2019_ncov/nucl/v6/ncov'
+    String  method      = 'blastn'
+    Int     outfmt      = 7
+    Float   evalue      = 10
+    String  Outfile     = basename(queryfa)+'.blast_result.txt'
+    Int     threads     = 8
+  }
+  if (method == 'blastp') {
+    call runblastp{
+      input:
+        Fname      = fname,
+        Queryfa    = queryfa,
+        docker     = blast_docker,
+        outfmt     = outfmt,
+        evalue     = evalue,
+        Outfile    = Outfile,
+        threads    = threads
+    }
+  }
+  if ( method == 'blastn'){
+    call runblastn{
+      input:
+        Fname      = fname,
+        Queryfa    = queryfa,
+        docker     = blast_docker,
+        outfmt     = outfmt,
+        evalue     = evalue,
+        Outfile    = Outfile,
+        threads    = threads
+    }
+  }
+  if ( method == 'blastx'){
+    call runblastx{
+      input:
+        Fname      = fname,
+        Queryfa    = queryfa,
+        docker     = blast_docker,
+        outfmt     = outfmt,
+        evalue     = evalue,
+        Outfile    = Outfile,
+        threads    = threads
+    }
+  }
+  if ( method == 'queryfa'){
+    call runtblastn{
+      input:
+        Fname      = fname,
+        Queryfa    = queryfa,
+        docker     = blast_docker,
+        outfmt     = outfmt,
+        evalue     = evalue,
+        Outfile    = Outfile,
+        threads    = threads
+    }
+  }
+  if ( method == 'tblastx'){
+    call runtblastx{
+      input:
+        Fname      = fname,
+        Queryfa    = queryfa,
+        docker     = blast_docker,
+        outfmt     = outfmt,
+        evalue     = evalue,
+        Outfile    = Outfile,
+        threads    = threads
+    }
+  }
+  output {
+    File fina_output =select_first([runtblastx.out,runblastp.out,runblastn.out,runblastx.out,runtblastn.out])
+  }
+}
+
+task runblastn {
+  input {
+    String  docker
+    File    Queryfa
+    String  Fname
+    String  Outfile
+    Int threads
+    #blast optional
+    Int     outfmt
+    Int     max_target_seqs = 100
+    Float   evalue
+    Int     word_size       = 28
+    Int     reward          = 1
+    Int     penalty         = -2
+    String  strand          = 'both'
+    Int     gapopen         = 0
+    Int     gapextend       = 0
+    String  dust            = "'20 64 1'"
+    Int?    max_hsps
+    String  tasks           = "megablast"
+    String?   taxids
+    String? negative_taxids
+    Boolean lcase_masking   = false
+  }
+  runtime{
+    docker : docker
+    cpu    : "8"
+    memory : "16G"
+  }
+  command {
+    set -e
+    blastn -db "${Fname}" \
+    -show_gis \
+    -query ${Queryfa} \
+    -outfmt ${outfmt} \
+    -out     ${Outfile} \
+    -max_target_seqs ${max_target_seqs} \
+    -evalue ${evalue} \
+    -word_size ${word_size} \
+    -penalty ${penalty} \
+    -reward  ${reward} \
+    -dust ${dust} \
+    -gapopen ${gapopen} \
+    -gapextend ${gapextend} \
+    -task ${tasks} \
+    -strand  ${strand} \
+    -num_threads ${threads} \
+    ${true='-lcase_masking' false='' lcase_masking} ${"-max_hsps "+max_hsps} ${"-taxids " +taxids} ${"-negative_taxids " +negative_taxids}\
+
+  }
+  output {
+    File out = "${Outfile}"
+  }
+}
+
+task runblastp {
+  input {
+    String  docker
+    File    Queryfa
+    String  Fname
+    #blast optional
+    Int     outfmt
+    String  Outfile
+    Float   evalue
+    Int threads
+    Int     max_target_seqs  = 100
+    Int     word_size        = 6
+    String seg               = "no"
+    String comp_based_stats  = "2"
+    String matrix            = "BLOSUM62"
+    Int     gapopen          = 11
+    Int     gapextend        = 1
+    Int?    max_hsps
+    String?   taxids
+    String? negative_taxids
+    Boolean lcase_masking    = false
+  }
+  runtime{
+    docker : docker
+    cpu    : "8"
+    memory : "16G"
+  }
+  command {
+    set -e
+    blastp -db "${Fname}" \
+    -query ${Queryfa} \
+    -outfmt ${outfmt} \
+    -out     ${Outfile} \
+    -max_target_seqs ${max_target_seqs} \
+    -comp_based_stats ${comp_based_stats} \
+    -evalue ${evalue} \
+    -word_size ${word_size} \
+    -matrix   ${matrix} \
+    -seg     ${seg} \
+    -gapopen ${gapopen} \
+    -gapextend ${gapextend} \
+    -num_threads ${threads} \
+    ${true='-lcase_masking' false='' lcase_masking} ${"-max_hsps "+max_hsps} ${"-taxids " +taxids} ${"-negative_taxids " +negative_taxids} \
+
+  }
+  output {
+    File out = "${Outfile}"
+  }
+}
+
+task runblastx {
+  input {
+    File   Queryfa
+    String Fname
+    Int    outfmt
+    Float  evalue
+    String Outfile
+    String docker
+    Int     threads
+    Int    max_target_seqs  =  100
+    Int    word_size        =  6
+    String seg              =  "'12 2.2 2.5'"
+    String comp_based_stats =  "2"
+    String matrix           =  "BLOSUM62"
+    Int    gapopen          =  11
+    Int    gapextend        =  1
+    String?   taxids
+    String? negative_taxids
+    Int?    max_hsps
+    Boolean lcase_masking    = false
+  }
+  runtime{
+    docker : docker
+    cpu   : "8"
+    memory : "16G"
+  }
+  command {
+    set -e
+    blastx -db "${Fname}" \
+    -query ${Queryfa} \
+    -outfmt ${outfmt} \
+    -out     ${Outfile} \
+    -max_target_seqs ${max_target_seqs} \
+    -comp_based_stats ${comp_based_stats} \
+    -evalue ${evalue} \
+    -word_size ${word_size} \
+    -matrix   ${matrix} \
+    -seg     ${seg} \
+    -gapopen ${gapopen} \
+    -gapextend ${gapextend} \
+    -num_threads ${threads} \
+    ${true='-lcase_masking' false='' lcase_masking} ${"-max_hsps "+max_hsps} ${"-taxids " +taxids} ${"-negative_taxids " +negative_taxids}\
+
+  }
+  output {
+    File out = "$${Outfile}"
+  }
+}
+
+task runtblastn {
+  input {
+    File   Queryfa
+    String Fname
+    Int    outfmt
+    Float  evalue
+    String Outfile
+    String docker
+    Int    threads
+    Int    max_target_seqs  = 100
+    Int    word_size        = 6
+    String seg              = "'12 2.2 2.5'"
+    String comp_based_stats = "2"
+    String matrix           = "BLOSUM62"
+    Int    gapopen          = 11
+    Int    gapextend        = 1
+    Boolean lcase_masking   = false
+    Int?    max_hsps
+    String?   taxids
+    String? negative_taxids
+  }
+  runtime{
+    docker :docker
+    cpu    : "8"
+    memory : "16G"
+  }
+  command {
+    set -e
+    tblastn -db "${Fname}" \
+    -query ${Queryfa} \
+    -outfmt ${outfmt} \
+    -out    ${Outfile} \
+    -max_target_seqs ${max_target_seqs} \
+    -comp_based_stats ${comp_based_stats} \
+    -evalue ${evalue} \
+    -word_size ${word_size} \
+    -matrix   ${matrix} \
+    -seg     ${seg} \
+    -gapopen ${gapopen} \
+    -gapextend ${gapextend} \
+    -num_threads ${threads} \
+    ${true='-lcase_masking' false='' lcase_masking} ${"-max_hsps "+max_hsps} ${"-taxids " +taxids} ${"-negative_taxids " +negative_taxids}\
+
+  }
+  output {
+    File out = "${Outfile}"
+  }
+}
+
+task runtblastx {
+  input {
+    File   Queryfa
+    String Fname
+    Int    outfmt
+    String Outfile
+    Int threads
+    Float  evalue
+    String docker
+    String?   taxids
+    Int    word_size        = 3
+    Int    max_target_seqs  = 100
+    String seg              = "'12 2.2 2.5'"
+    String matrix           = "BLOSUM62"
+    Boolean lcase_masking   = false
+    String? negative_taxids
+    Int?    max_hsps
+  }
+  runtime{
+    docker :docker
+    cpu    : "8"
+    memory : "16G"
+  }
+  command {
+    set -e
+    tblastx -db "${Fname}" \
+    -query ${Queryfa} \
+    -outfmt ${outfmt} \
+    -out     ${Outfile} \
+    -max_target_seqs ${max_target_seqs} \
+    -evalue ${evalue} \
+    -word_size ${word_size} \
+    -matrix   ${matrix} \
+    -seg     ${seg} \
+    -num_threads ${threads} \
+    ${true='-lcase_masking' false='' lcase_masking} ${"-max_hsps "+max_hsps} ${"-taxids " +taxids} ${"-negative_taxids " +negative_taxids}\
+  }
+  output {
+    File out = "${Outfile}"
+  }
+}
+
+